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{{Short description|none}} <!-- "none" is a legitimate description when the title is already adequate; see ] -->
{{Infobox hurricane season nopic| name=1970 Pacific hurricane season
{{Infobox hurricane season
| first storm formed=], ]
| Basin=EPac
| last storm dissipated=], ]
| Year=1970
| strongest storm=''Lorraine'' - 963 ], Patricia - 95&nbsp;]
| Track=1970 Pacific hurricane season summary map.png
| total storms=19
| First storm formed=May 30, 1970
| major storms=0
| Last storm dissipated=November 8, 1970
| total damages=minimal direct, 1 million indirect (1970 ])
| Strongest storm name=Lorraine
| total fatalities= 0 direct, 22 indirect
| Strongest storm pressure=963
| basin=Pacific hurricane
| Strongest storm winds=85
| five seasons=], ], '''1970''', ], ]
| Average wind speed=1
| Total depressions=21
| Total storms=19
| Total hurricanes=5
| Total intense=0
| Fatalities=0 direct, 22 indirect
| Damages=
| Inflated=
| five seasons=], ], '''1970''', ], ]
|Atlantic season=1970 Atlantic hurricane season
|West Pacific season=1970 Pacific typhoon season
|North Indian season=1970 North Indian Ocean cyclone season
}} }}
The '''1970 Pacific hurricane season''' was an active ] ] season, especially during its early months. It officially started on May&nbsp;15, 1970, in the eastern Pacific Ocean (east of ]), and on June&nbsp;1, 1970, in the central Pacific (between 140°W and the ]). It ended on November&nbsp;30, 1970, in both regions. These dates conventionally delimit the period of each year when most ] occurs in these parts of the Pacific.


This season had an above average number of storms. There were 21&nbsp;]s, of which 18&nbsp;reached tropical storm strength. Four storms became hurricanes, of which none reached major hurricane strength. In the central Pacific, one hurricane and one tropical depression formed. One of the depressions crossed the Date Line to become a ] in the western Pacific.
The '''1970 Pacific hurricane season''' began on ], ] in the east ], and on ], 1970 in the central Pacific. It ended on ], ]. These dates conventionally delimit the period of time when ]s form in the eastern Pacific Ocean.


__TOC__
==Activity==
{{Clear}}
This season had an above average number of storms. There were twenty-one tropical cyclones, of which eighteen reached tropical storm strength. Four storms became hurricanes, of which none reached major hurricane strength. In the central Pacific, one hurricane and one tropical deprssion formed. One of the depressions crossed the dateline to become a typhoon.


===Hurricane Adele=== == Systems ==
{{center|
The first storm and hurricane of the season developed on ] southwest of ]. Adele tracked westward, becoming a hurricane on ]. It slowly died down, and dissipated on ]. Despite that it remained away from any land masses, Adele was retired after this season for unknown reasons.
<timeline>
ImageSize = width:800 height:200
PlotArea = top:10 bottom:80 right:20 left:20
Legend = columns:3 left:30 top:58 columnwidth:270


AlignBars = early
===Tropical Storm Eileen===
DateFormat = dd/mm/yyyy
A tropical depression formed just off the southern coast of Mexico on ]. It headed northwestward, reaching storm strength on ]. The next day, Eileen turned to the northeast, reached a peak of 45 mph winds, and hit western Mexico.
Period = from:01/05/1970 till:01/12/1970
TimeAxis = orientation:horizontal
ScaleMinor = grid:black unit:month increment:1 start:01/05/1970


Colors =
===Tropical Storm Ione===
id:canvas value:gray(0.88)
A tropical depression developed off the southern coast of Mexico on ]. It tracked westward, reaching tropical storm strength on the two days later before dissipating on ]. What was unusual about the system was that another tropical storm developed just to its northeast on ]. That storm, also named Ione, tracked northward, reaching a peak of 60 mph winds before dissipating on ].
id:GP value:red
id:TD value:rgb(0.43,0.76,0.92) legend:Tropical_Depression_=_≤38_mph_(≤62_km/h)
id:TS value:rgb(0.3,1,1) legend:Tropical_Storm_=_39–73_mph_(63–117_km/h)
id:C1 value:rgb(1,1,0.85) legend:Category_1_=_74–95_mph_(118–153_km/h)
id:C2 value:rgb(1,0.85,0.55) legend:Category_2_=_96–110_mph_(154–177_km/h)
id:C3 value:rgb(1,0.62,0.35) legend:Category_3_=_111–129_mph_(178–208_km/h)
id:C4 value:rgb(1,0.45,0.54) legend:Category_4_=_130–156_mph_(209–251_km/h)
id:C5 value:rgb(0.55,0.46,0.90) legend:Category_5_=_≥157_mph_(≥252_km/h)
Backgroundcolors = canvas:canvas


BarData =
===Hurricane Lorraine===
barset:Hurricane
Tropical Storm Lorraine, which formed on ] south of Mexico, intensified to a hurricane on the 20th. Two days later over open waters, it reached a peak of 95 mph (153 km/h) winds, but estimates from the ] estimated it had winds of 115 ] (185 ]). Without a chance to strengthen further, Lorraine weakened, finally dissipating on ] due to dry air.
bar:Month


PlotData=
===Tropical Storm Maggie===
barset:Hurricane width:11 align:left fontsize:S shift:(4,-4) anchor:till
A small cloud vortex slowly organized into a tropical depression on ] while southeast of ]. It headed west-northwestward, becoming a tropical storm that night and reaching a peak of 60 mph (97 km/h) winds on ]. A westward turn saved Hawaii from a direct hit, but Maggie still brought strong surf and heavy yet beneficial rain to the island of ].
from:30/05/1970 till:07/06/1970 color:C1 text:"Adele (C1)"
from:10/06/1970 till:12/06/1970 color:TS text:"Blanca (TS)"
from:17/06/1970 till:21/06/1970 color:TS text:"Connie (TS)"
from:19/06/1970 till:20/06/1970 color:TD text:"Dolores (TD)"
from:26/06/1970 till:29/06/1970 color:TS text:"Eileen (TS)"
from:01/07/1970 till:10/07/1970 color:C2 text:"Francesca (C2)"
from:14/07/1970 till:21/07/1970 color:TS text:"Gretchen (TS)"
barset:break
from:16/07/1970 till:20/07/1970 color:TS text:"Helga (TS)"
from:22/07/1970 till:26/07/1970 color:TS text:"Ione One (TS)"
from:24/07/1970 till:25/07/1970 color:TS text:"Ione Two (TS)"
from:29/07/1970 till:04/08/1970 color:TS text:"Joyce (TS)"
from:05/08/1970 till:08/08/1970 color:TS text:"Kristen (TS)"
from:16/08/1970 till:27/08/1970 color:C2 text:"Lorraine (C2)"
from:20/08/1970 till:27/08/1970 color:TS text:"Maggie (TS)"
barset:break
from:31/08/1970 till:06/09/1970 color:TS text:"] (TS)"
from:01/09/1970 till:04/09/1970 color:C1 text:"Dot (C1)"
from:07/09/1970 till:09/09/1970 color:TS text:"Orlene (TS)"
from:04/10/1970 till:11/10/1970 color:C2 text:"Patricia (C2)"
from:21/10/1970 till:23/10/1970 color:TS text:"Rosalie (TS)"
from:01/11/1970 till:08/11/1970 color:TS text:"Selma (TS)"
bar:Month width:5 align:center fontsize:S shift:(0,-20) anchor:middle color:canvas
from:01/05/1970 till:01/06/1970 text:May
from:01/06/1970 till:01/07/1970 text:June
from:01/07/1970 till:01/08/1970 text:July
from:01/08/1970 till:01/09/1970 text:August
from:01/09/1970 till:01/10/1970 text:September
from:01/10/1970 till:01/11/1970 text:October
from:01/11/1970 till:01/12/1970 text:November


TextData =
===Tropical Storm Norma===
pos:(570,30)
Norma was an indirect but essential cause of a flood disaster in Arizona that became known as the "Labor Day Storm of 1970". A depression formed ] and rapidly intensified into a tropical storm. Moving rapidly, it headed out to sea before slowing down and weakening. Norma's circulation fed humid unstable air into a large extratropical cyclone over ]. As Norma dissipated, record rains fell over the state from ] to ].
text:"(From the"
pos:(617,30)
text:"])"


</timeline>
The rains were deadly. There were a total of 22 deaths, including 14 from a ] on a creek. The damage amounted to over 1 million dollars.
}}


===Hurricane Dot=== === Hurricane Adele ===
{{Infobox Hurricane Small
A tropical disturbance, possibly the remnants of Tropical Storm Maggie, became a tropical depression on ] to the northwest of Hawaii. It moved to the northwest, coming within miles of the ] and ] but remaining in the Central Pacific. Dot turned to the northeast, reaching tropical storm strength on ] and hurricane strength ] before being absorbed by a cold core system the next day. When Dot became a hurricane at 35º north, it became the second highest latitude for a storm to reach hurricane strength, only behind ] of the ].
|Basin=EPac
|Image=AdeleJun119702106z.jpg
|Track=Adele 1970 track.png
|Formed=May 30
|Dissipated=June 7
|1-min winds=75
|Prepressure=≤
|Pressure=992
}}
An area of low pressure lacked strong convection until May&nbsp;30, when it strengthened into Tropical Depression One-E. On May&nbsp;31, the system further intensified into Tropical Storm Adele, the first named storm of the season. As Adele tracked westward, it strengthened into a hurricane on June&nbsp;1 and reached its peak intensity soon afterward. As Adele moved west, a hostile environment caused it to weaken into a tropical storm. Adele further weakened, and it was downgraded into a depression on June&nbsp;7. It degenerated into an ] later that day.
{{clear}}


===Tropical Storm Orlene=== === Tropical Storm Blanca ===
{{Infobox Hurricane Small
65 mph Tropical Storm Orlene hit Mexico in the ] on ], having maintained a northeast track for its short lifetime.
|Basin=EPac
|Image=BlancaJun1019702213z.jpg
|Track=Blanca 1970 track.png
|Formed=June 10
|Dissipated=June 12
|1-min winds=50
|Pressure=1002
}}
The tropical disturbance that became Blanca was first noted on June 8 from satellite pictures. The new disturbance would reach tropical storm strength 24&nbsp;hours later. Blanca moved in a northwest direction throughout its short life, dissipating on June 12.
{{clear}}


=== Tropical Storm Connie ===
===Hurricane Patricia===
{{Infobox Hurricane Small
Hurricane Patricia, the strongest storm of the season with winds of 95 knots, remained over the open waters of the Eastern Pacific. It lasted from ] to ].
|Basin=EPac
|Image=ConnieJun1719702222z.jpg
|Track=Connie 1970 track.png
|Formed=June 17
|Dissipated=June 21
|1-min winds=45
|Pressure=1001
}}
Near the same location where Hurricane Adele formed two weeks earlier, a disturbance was noted on June 13. The disturbance abruptly became a tropical storm on June 17. The newly named Connie moved slowly to the northwest, reaching a peak intensity of {{convert|50|mi/h|km/h|abbr=on}} on June 18. Connie started weakening on June 19, finally dissipating on June 21 after stalling {{convert|118|mi|km|abbr=on}} from Clarion Island.
{{clear}}


===Tropical Storm Selma=== === Tropical Depression Dolores ===
{{Infobox Hurricane Small
The final storm of the season, Tropical Storm Selma, developed on ] to the southwest of Mexico. It meandered to the north, turning to the northeast and northwest before heading southeastward and dissipating on ].
|Basin=EPac
|Image=Tropical Depression Dolores 1970.JPG
|Track=Dolores 1970 track.png
|Formed=June 19
|Dissipated=June 20
|1-min winds=25
}}
A disturbance first noted on June 19 had efficient outflow to be called a tropical depression. Satellite photos taken the same day revealed cloud structure that resembled a tropical storm forming, resulting in the system being called Dolores. The day after, no traces of a storm or of "Dolores" were found by reconnaissance. Post season analysis revealed Dolores to have only been a tropical depression.
{{clear}}


==1970 Storm Names== === Tropical Storm Eileen ===
{{Infobox Hurricane Small
These names were used for storms that formed in the east Pacific Ocean this season. It is the same list used in the ]. Names not retired from this list were used again in the ]. Storms were named Norma, Orlene, Patricia, Rosalie, and Selma for the first time this season. Names not used this year are marked in <font style="color: #888;">gray</font>.
|Basin=EPac
|Image=EileenJun281970.jpg
|Track=Eileen 1970 track.png
|Formed=June 26
|Dissipated=June 30
|1-min winds=40
|Pressure=1005
}}
A tropical depression formed just off the southern coast of Mexico on June 26. It headed northwestward, reaching storm strength on June 28. The next day, Eileen turned to the northeast, reached a peak of {{convert|45|mi/h|km/h|abbr=on}} winds, and hit western Mexico.
{{clear}}


=== Hurricane Francesca ===
One storm, Ione, was treated as one storm operationally but was found to have been two storms in post-analysis. Another storm, Dolores, was found to have been a tropical depression in post-season analysis and shouldn't have been named.
{{Infobox Hurricane Small
|Basin=EPac
|Image=FrancescaJuly61970ITOS1.gif
|Track=Francesca 1970 track.png
|Formed=July 1
|Dissipated=July 10
|1-min winds=85
|Prepressure=≤
|Pressure=991
}}
Francesca was a Category 2 hurricane which was, for a period of time, obscured by a cap of clouds above the hurricane's eye, distorting the appearance of the hurricane. The precursor disturbance to Hurricane Francesca was first noticed on July 1. The system became a tropical depression later that day and reached tropical storm strength the next day. On July 3, data from a ship indicated winds of near {{convert|100|mi/h|km/h|abbr=on}}, which indicate a storm of Category&nbsp;2 strength, near the center of Francesca. The cloud cap, which remained over the hurricane since it first became a hurricane, started to move off the lower clouds around the center of the system around July 5. A center fix was obtained, but the maximum sustained winds were unobtainable from the sea surface because of cloud cover in and around the center. Francesca started weakening on July 6, a fact made clear by reconnaissance which indicated that the system had weakened to a tropical storm. The further weakening was obscured by the cloud cover. The final reconnaissance on the weakening system was reported on July 8, two days before Francesca dissipated.
{{clear}}

=== Tropical Storm Gretchen ===
{{Infobox Hurricane Small
|Basin=EPac
|Image=GretchenJuly1719702151z.gif
|Track=Gretchen 1970 track.png
|Formed=July 14
|Dissipated=July 21
|1-min winds=45
|Pressure=1000
}}
Gretchen was first noticed on satellite imagery on July 14. From then on out, Gretchen was a hard storm to predict, leading to large errors in forecasting. The storm dissipated on July 21.
{{clear}}

=== Tropical Storm Helga ===
{{Infobox Hurricane Small
|Basin=EPac
|Image=HelgaJuly1719702151z.gif
|Track=Helga 1970 track.png
|Formed=July 16
|Dissipated=July 20
|1-min winds=50
|Pressure=1007
}}
The system that became Helga was first noticed on July 16. The next day, reconnaissance found a minimal tropical storm with winds of only {{convert|40|mi/h|km/h|abbr=on}}. Based on satellite imagery, Helga was believed to be gaining strength as it approached Baja California. At one point during intensification, the storm abruptly started weakening, and on July 19, after stalling less than <span style="white-space:nowrap">118&nbsp;miles&nbsp;(190&nbsp;km)</span> south of the tip of Baja California, Helga dissipated.
{{clear}}

=== Tropical Storm Ione 1 ===
{{Infobox Hurricane Small
|Basin=EPac
|Image=Ione2Jul2519702141ITOS1.gif
|Track=Ione 2 1970 track.png
|Formed=July 22
|Dissipated=July 26
|1-min winds=45
}}
A tropical depression developed off the southern coast of Mexico on July 22. A larger intensifying tropical cyclone was spotted by satellite at 2235 on the 24th near 17°N., 111°W. When the expanding circulation of this storm center reached the area of Ione, winds in the latter area decreased and it disappeared abruptly. The second storm, which was also named Ione, moved north-northwestward and began to weaken. Ione reached maximum sustained winds of 45 knots on the 25th near 20. N.,112°W. These winds decreased to 25 knots the next day as storm activity faded rapidly near 16 N., 113°W'.
What was unusual about the system was that another tropical storm developed just to its northeast on July 24. That storm, also named Ione, tracked northward, reaching a peak of {{convert|60|mi/h|km/h|abbr=on}} winds before dissipating on July 25. Operationally, these were considered to be the same storm.
{{clear}}

=== Tropical Storm Ione 2 ===
{{Infobox Hurricane Small
|Basin=EPac
|Image=Ione1Jul2519702141ITOS1.gif
|Track=Ione 1 1970 track.png
|Formed=July 24
|Dissipated=July 25
|1-min winds=50
|Pressure=1007
}}
A tropical depression was discovered near 14°N.,102°W., at 1800 on July 22, but it became disorganized as seen on satellite pictures the next day. Later
events indicate it was splitting into two tropical cyclones, both of which were to attain tropical storm strength. The tropical storm first called lone
was encountered by the KANIKAWA MARU at 2100 on July 24. That ship was buffeted by 48-kn southeasterly winds and 15-ft seas near 21°N, 107°W. The storm washed
out the next day.<ref>Climatological Data National Summary 1970</ref>
{{clear}}

=== Tropical Storm Joyce ===
{{Infobox Hurricane Small
|Basin=EPac
|Image=Tropical Storm Joyce 1970.JPG
|Track=Joyce 1970 track.png
|Formed=July 29
|Dissipated=August 4
|1-min winds=50
|Pressure=1000
}}
A broad, flat low-pressure area persisted south of Baja California after Ione dissipated. On July 29, a small low circulation developed with a center about <span style="white-space:nowrap">120&nbsp;nautical miles&nbsp;(220&nbsp;km)</span> south of Manzanillo. The system was given the name Joyce after winds of {{convert|40|mi/h|km/h|abbr=on}} were reported by a ship. In a similar way to Hurricane Francesca, Tropical Storm Joyce's low level center was unclear due to a cap of cirrus clouds. Joyce reached its peak intensity on July 31 with winds of near {{convert|60|mi/h|km/h|abbr=on}} before weakening, becoming a depression on August 1. Joyce dissipated on August 4.
{{clear}}

=== Tropical Storm Kristen ===
{{Infobox Hurricane Small
|Basin=EPac
|Image=Sat19700807itos1Kristen.png
|Track=Kristen 1970 track.png
|Formed=August 5
|Dissipated=August 8
|1-min winds=45
|Pressure=1005
}}
Kristen was a loosely organized storm that formed from a disturbance that was causing squalls near the Mexican coast. Tropical storm-force winds were found on August 5. Kristen was tracked by ship reports and satellite pictures. Kristen reached its peak intensity of {{convert|50|mi/h|km/h|abbr=on}} winds on August 6. The storm dissipated on August 8 while over cold water.
{{clear}}

=== Hurricane Lorraine ===
{{Infobox Hurricane Small
|Basin=EPac
|Image=LorraineAug2219702300UTCITOS1.gif
|Track=Lorraine 1970 track.png
|Formed=August 16
|Dissipated=August 27
|1-min winds=85
|Pressure=963
}}
Tropical Storm Lorraine, which formed on August 16 south of Mexico, intensified to a hurricane on the 20th. Two days later over open waters, it reached a peak of 95&nbsp;mph (153&nbsp;km/h) winds, but estimates from the ] estimated it had winds of 115&nbsp;mph (185&nbsp;km/h). Without a chance to strengthen further, Lorraine weakened, finally dissipating on August 27 due to dry air.
{{clear}}

=== Tropical Storm Maggie ===
{{Infobox Hurricane Small
|Basin=EPac
|Image=Tropical Storm Maggie.JPG
|Track=Maggie 1970 track.png
|Formed=August 20
|Dissipated=August 27
|1-min winds=50
|Pressure=993
}}
A flat low-pressure system appeared in an area of showers to the west-southwest of hurricane Lorraine around 1800 on the 20th. The French refrigerated
cargo carrier BIAFRA was buffeted by 38-kn southerly winds, with a barometer reading 1006 mbar, near 13'N, 132'W, by the soon to be named tropical storm Maggie at 0000 on the 21st. Maggie intensified slowly while moving west-northwestward at 9 kn; her maximum winds were estimated at 55 kn at 0300 on the 25th. Maggie passed about 80&nbsp;mi south of the island of Hawaii on the 25th, dumping torrential rains over the big island. Rainfall amounts ranged from 10 to 15 in on the windward side of the island from the Hamuka coast
to Puna and from 1 to 7 in on the leeward side. Maggie was downgraded to a tropical depression at 0900 on the 26th near 18N, 157W.
A westward turn saved Hawaii from a direct hit, but Maggie still brought strong surf and heavy yet beneficial rain to the island of ]. There is some evidence that the remains of Maggie redeveloped into Hurricane Dot in the Central Pacific on September 1.
{{clear}}

=== Tropical Storm Norma ===
{{Infobox Hurricane Small
|Basin=EPAC
|Image=Tropical Storm Norma (1970).JPG
|Track=Norma 1970 track.png
|Formed=August 31
|Dissipated=September 6
|1-min winds=50
|Pressure=988
}}
{{Main|Tropical Storm Norma (1970)}}
Norma was an indirect but essential cause of a flood disaster in Arizona that became known as the "Labor Day Storm of 1970". A depression formed August 31 and rapidly intensified into a tropical storm. Moving rapidly, it headed out to sea before slowing down and weakening. Norma's circulation fed humid unstable air into a large extratropical cyclone over ]. As Norma dissipated, record rains fell over the state from September 4 to September 6.

The rains were deadly. There were a total of 22 deaths, including 14 from a ] on a creek. The damage amounted to over 1&nbsp;million dollars.
{{clear}}

=== Hurricane Dot ===
{{Infobox Hurricane Small
|Basin=EPac
|Image=Dot 1970 track.png
|Formed=September 1
|Dissipated=September 4
|1-min winds=70
|Pressure=993
}}
A tropical disturbance, possibly the remnants of Tropical Storm Maggie, became a tropical depression on September 1 to the northwest of Hawaii. It moved to the northwest, coming within miles of the ] and ] but remaining in the Central Pacific. Dot turned to the northeast, reaching tropical storm strength on September 2 and hurricane strength September 3 before being absorbed by a cold core system the next day. When Dot became a hurricane at 35° north, it became the highest latitude for a storm to reach hurricane strength east of the International Dateline. This record was soon eclipsed by ] of the ]. A flight flown into Dot also flew into ].
{{clear}}

=== Tropical Storm Orlene ===
{{Infobox Hurricane Small
|Basin=EPac
|Image=Orlene 1970-09-08 1725Z.jpg
|Track=Orlene 1970 track.png
|Formed=September 7
|Dissipated=September 9
|1-min winds=55
|Pressure=995
}}
{{convert|65|mi/h|km/h|abbr=on}} Tropical Storm Orlene hit Mexico in eastern ] on September 8, having maintained a northeast track for its short lifetime.
{{clear}}

=== Hurricane Patricia ===
{{Infobox Hurricane Small
|Basin=EPac
|Image=Patriciaoct819702304UTCITOS1.gif
|Track=Patricia 1970 track.png
|Formed=October 4
|Dissipated=October 11
|1-min winds=85
|Pressure=972
}}
Hurricane Patricia was a strong Category 2 hurricane with winds of 95&nbsp;mph, Patricia formed on October 4 and dissipated on October 11.
{{clear}}

=== Tropical Storm Rosalie ===
{{Infobox Hurricane Small
|Basin=EPac
|Image=RosalieOct2219702249UTCITOS1.gif
|Track=Rosalie 1970 track.png
|Formed=October 21
|Dissipated=October 23
|1-min winds=48
|Pressure=1006
}}
Rosalie's existence was confirmed on October 21 by observation from a ship. Reconnaissance on the 22nd reported a central pressure of 1006 mb. After a slight regeneration on the 23rd, Rosalie began rapid dissipation, finally dissipating on the 23rd.
{{clear}}

=== Tropical Storm Selma ===
{{Infobox Hurricane Small
|Basin=EPac
|Image=SelmaNov319702234ITOS1.gif
|Track=Selma 1970 track.png
|Formed=November 1
|Dissipated=November 8
|1-min winds=60
|Pressure=995
}}
The final storm of the season, Tropical Storm Selma, developed on November 1 to the southwest of Mexico. It meandered to the north, turning to the northeast and northwest before heading southeastward and dissipating on November 8.
{{clear}}

== Storm names ==
{{Tropical cyclone naming}}
The following list of names was used for named storms that formed in the North Pacific Ocean east of ] in 1970.<ref name="NHOP 70">{{cite report|url=https://www.aoml.noaa.gov/general/lib/lib1/nhclib/Publications/NatHurricaneOpsPlans/HOPs-1970.pdf|pages=95, 97|publisher=] Office of the Federal Coordinator for Meteorological Services and Supporting Research|location=Washington, D.C.|title=National Hurricane Operations Plan|date=May 1970|access-date=February 27, 2024}}</ref> It was the same list used in the ], with the exception of ''Kristen'', which replaced ''Kirsten''.<ref name="GPNov07">{{cite web|url=http://australiasevereweather.com/cyclones/2008/summ0711a.htm|title=Monthly Global Tropical Cyclone Summary: November 2007 First Installment|first=Gary|last=Padgett|date=July 11, 2008|publisher=Australian Severe Weather|accessdate=February 27, 2024}}</ref> Storms were named ''Kristen'', ''Norma'', ''Orlene'', ''Patricia'', ''Rosalie'', and ''Selma'' for the first time this season.<ref name=ATWC>{{cite web|access-date=February 27, 2024|title=Eastern North Pacific Tropical Cyclone Name History|publisher=Atlantic Tropical Weather Center|url=http://www.atwc.org/pachist.txt|archive-url= https://web.archive.org/web/20070929105925/http://www.atwc.org/pachist.txt|archive-date=September 29, 2007|url-status=dead}}</ref> The name ''Kristen'' was later respelled as ''Kirsten'' for 1974.


{| width="90%" {| width="90%"
Line 57: Line 378:
* Adele * Adele
* Blanca * Blanca
* Connie * Connie
* Dolores * Dolores
* Eileen * Eileen
* Francesca * Francesca
* Gretchen * Gretchen
| |
* Helga * Helga
* Ione * Ione
* Joyce * Joyce
* Kristen * Kristen
* Lorraine * Lorraine{{thin space}}*
* Maggie * Maggie{{thin space}}*
* Norma * ]
| |
* Orlene * Orlene
* Patricia * Patricia
* Rosalie * Rosalie
* Selma * Selma
* {{Tcname unused|Toni}}
* <div style="color: #888;">Toni (unused)</div>
* {{Tcname unused|Viviam}}
* <div style="color: #888;">Vivian (unused)</div>
* {{Tcname unused|Winona}}
* <div style="color: #888;">Winona (unused)</div>
|} |}


One named storm, listed below, formed in the North Pacific between 140°W and the ] in 1970. At the time, storm names within this region were assigned by the ] on ].<ref name="NHOP 70"/><ref name=ATWC/> Named storms in the table above that crossed into the area during the season are noted (*).<ref name="Hawaii">{{cite report|author=Pao-Shin Chu|author2=Peng Wu|publisher=University of Hawaii-Manoa|year=2008|access-date=February 27, 2024|title=Climatic Atlas of Tropical Cyclone Tracks over the Central North Pacific|url=http://files.hawaii.gov/dbedt/op/czm/initiative/hazard/climatic_atlas_of_tropical_cyclone.pdf|archive-date=October 23, 2014|archive-url=https://web.archive.org/web/20141023054832/http://files.hawaii.gov/dbedt/op/czm/initiative/hazard/climatic_atlas_of_tropical_cyclone.pdf|url-status=live}}</ref>
The central Pacific used names and numbers from the west Pacific's typhoon list. One name&mdash; Dot&mdash; was required.


{| width="90%"
The name Adele was retired from this list for no particular reason. It was replaced in the ] with Aletta.
|
* Dot
|}


=== Retirement ===
This is the first and only time that the name Kristen was used. In the ] the name Kirsten was used. It was changed to Kristen this year, perhaps due to a clerical error. In the ], it reverted back to Kirsten.
{{See also|List of retired Pacific hurricane names}}
The name ''Adele'' was later retired without explanation.<ref>{{cite web|url=https://www.nhc.noaa.gov/aboutnames_history.shtml|title=Tropical Cyclone Naming History and Retired Names|publisher=National Hurricane Center|location=Miami, Florida|access-date=February 27, 2024}}</ref> It was replaced with ''Aletta'' for the ].<ref name="GPNov07"/>


==Administrative Changes== == Administrative changes ==
This is the first season that the ]-based ] started issuing advisories on tropical cyclones in the eastern north Pacific. It replaced the previous forecaster, ]. Also. the ] started to issue advisories on tropical cyclones in its area of responsibility this season. It replaced the ].{{Citation needed|date=February 2024|reason=These statements need a reliable source}}
Around this year, the ] started giving advisories and forecasts for this basin. The exact year is not known. It is also not known what entity was responsible for this basin before the EPHC.


==See also== == See also ==
{{Portal|Tropical cyclones}}
{{tcportal}}
*] * ]
*] * ]
*] * ]
*] * ]
*] * ]
* Australian cyclone seasons: ], ]
*]
* South Pacific cyclone seasons: ], ]
* South-West Indian Ocean cyclone seasons: ], ]


==References== == References ==
{{Reflist}}
* accessed November 17, 2005
* accessed November 17, 2005 * accessed November 17, 2005
* accessed November 17, 2005 * accessed November 17, 2005
* accessed November 17, 2005 * accessed November 17, 2005


==External links== == External links ==
*
*

*
{{1970 Pacific hurricane season buttons}}
{{TC Decades|Year=1970|basin=Pacific|type=hurricane}}
{{Tropical cyclone season|1970}}


{{Hurricane season categories|Pacific hurricane|1970}} {{DEFAULTSORT:1970 Pacific Hurricane Season}}
]
]
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Latest revision as of 02:45, 18 December 2024

1970 Pacific hurricane season
Season summary map
Seasonal boundaries
First system formedMay 30, 1970
Last system dissipatedNovember 8, 1970
Strongest storm
NameLorraine
 • Maximum winds100 mph (155 km/h)
(1-minute sustained)
 • Lowest pressure963 mbar (hPa; 28.44 inHg)
Seasonal statistics
Total depressions21
Total storms19
Hurricanes5
Major hurricanes
(Cat. 3+)		0
Total fatalities0 direct, 22 indirect
Total damageUnknown
Related articles
Pacific hurricane seasons
1968, 1969, 1970, 1971, 1972

The 1970 Pacific hurricane season was an active Northern hemisphere hurricane season, especially during its early months. It officially started on May 15, 1970, in the eastern Pacific Ocean (east of 140°W), and on June 1, 1970, in the central Pacific (between 140°W and the International Date Line). It ended on November 30, 1970, in both regions. These dates conventionally delimit the period of each year when most tropical cyclogenesis occurs in these parts of the Pacific.

This season had an above average number of storms. There were 21 tropical cyclones, of which 18 reached tropical storm strength. Four storms became hurricanes, of which none reached major hurricane strength. In the central Pacific, one hurricane and one tropical depression formed. One of the depressions crossed the Date Line to become a typhoon in the western Pacific.

Systems

Tropical Storm Norma (1970)Saffir–Simpson Hurricane Scale

Hurricane Adele

Category 1 hurricane (SSHWS)
 
DurationMay 30 – June 7
Peak intensity85 mph (140 km/h) (1-min);
≤992 mbar (hPa)

An area of low pressure lacked strong convection until May 30, when it strengthened into Tropical Depression One-E. On May 31, the system further intensified into Tropical Storm Adele, the first named storm of the season. As Adele tracked westward, it strengthened into a hurricane on June 1 and reached its peak intensity soon afterward. As Adele moved west, a hostile environment caused it to weaken into a tropical storm. Adele further weakened, and it was downgraded into a depression on June 7. It degenerated into an open trough later that day.

Tropical Storm Blanca

Tropical storm (SSHWS)
 
DurationJune 10 – June 12
Peak intensity60 mph (95 km/h) (1-min);
1002 mbar (hPa)

The tropical disturbance that became Blanca was first noted on June 8 from satellite pictures. The new disturbance would reach tropical storm strength 24 hours later. Blanca moved in a northwest direction throughout its short life, dissipating on June 12.

Tropical Storm Connie

Tropical storm (SSHWS)
 
DurationJune 17 – June 21
Peak intensity50 mph (85 km/h) (1-min);
1001 mbar (hPa)

Near the same location where Hurricane Adele formed two weeks earlier, a disturbance was noted on June 13. The disturbance abruptly became a tropical storm on June 17. The newly named Connie moved slowly to the northwest, reaching a peak intensity of 50 mph (80 km/h) on June 18. Connie started weakening on June 19, finally dissipating on June 21 after stalling 118 mi (190 km) from Clarion Island.

Tropical Depression Dolores

Tropical depression (SSHWS)
 
DurationJune 19 – June 20
Peak intensity30 mph (45 km/h) (1-min);

A disturbance first noted on June 19 had efficient outflow to be called a tropical depression. Satellite photos taken the same day revealed cloud structure that resembled a tropical storm forming, resulting in the system being called Dolores. The day after, no traces of a storm or of "Dolores" were found by reconnaissance. Post season analysis revealed Dolores to have only been a tropical depression.

Tropical Storm Eileen

Tropical storm (SSHWS)
 
DurationJune 26 – June 30
Peak intensity45 mph (75 km/h) (1-min);
1005 mbar (hPa)

A tropical depression formed just off the southern coast of Mexico on June 26. It headed northwestward, reaching storm strength on June 28. The next day, Eileen turned to the northeast, reached a peak of 45 mph (72 km/h) winds, and hit western Mexico.

Hurricane Francesca

Category 2 hurricane (SSHWS)
 
DurationJuly 1 – July 10
Peak intensity100 mph (155 km/h) (1-min);
≤991 mbar (hPa)

Francesca was a Category 2 hurricane which was, for a period of time, obscured by a cap of clouds above the hurricane's eye, distorting the appearance of the hurricane. The precursor disturbance to Hurricane Francesca was first noticed on July 1. The system became a tropical depression later that day and reached tropical storm strength the next day. On July 3, data from a ship indicated winds of near 100 mph (160 km/h), which indicate a storm of Category 2 strength, near the center of Francesca. The cloud cap, which remained over the hurricane since it first became a hurricane, started to move off the lower clouds around the center of the system around July 5. A center fix was obtained, but the maximum sustained winds were unobtainable from the sea surface because of cloud cover in and around the center. Francesca started weakening on July 6, a fact made clear by reconnaissance which indicated that the system had weakened to a tropical storm. The further weakening was obscured by the cloud cover. The final reconnaissance on the weakening system was reported on July 8, two days before Francesca dissipated.

Tropical Storm Gretchen

Tropical storm (SSHWS)
 
DurationJuly 14 – July 21
Peak intensity50 mph (85 km/h) (1-min);
1000 mbar (hPa)

Gretchen was first noticed on satellite imagery on July 14. From then on out, Gretchen was a hard storm to predict, leading to large errors in forecasting. The storm dissipated on July 21.

Tropical Storm Helga

Tropical storm (SSHWS)
 
DurationJuly 16 – July 20
Peak intensity60 mph (95 km/h) (1-min);
1007 mbar (hPa)

The system that became Helga was first noticed on July 16. The next day, reconnaissance found a minimal tropical storm with winds of only 40 mph (64 km/h). Based on satellite imagery, Helga was believed to be gaining strength as it approached Baja California. At one point during intensification, the storm abruptly started weakening, and on July 19, after stalling less than 118 miles (190 km) south of the tip of Baja California, Helga dissipated.

Tropical Storm Ione 1

Tropical storm (SSHWS)
 
DurationJuly 22 – July 26
Peak intensity50 mph (85 km/h) (1-min);

A tropical depression developed off the southern coast of Mexico on July 22. A larger intensifying tropical cyclone was spotted by satellite at 2235 on the 24th near 17°N., 111°W. When the expanding circulation of this storm center reached the area of Ione, winds in the latter area decreased and it disappeared abruptly. The second storm, which was also named Ione, moved north-northwestward and began to weaken. Ione reached maximum sustained winds of 45 knots on the 25th near 20. N.,112°W. These winds decreased to 25 knots the next day as storm activity faded rapidly near 16 N., 113°W'. What was unusual about the system was that another tropical storm developed just to its northeast on July 24. That storm, also named Ione, tracked northward, reaching a peak of 60 mph (97 km/h) winds before dissipating on July 25. Operationally, these were considered to be the same storm.

Tropical Storm Ione 2

Tropical storm (SSHWS)
 
DurationJuly 24 – July 25
Peak intensity60 mph (95 km/h) (1-min);
1007 mbar (hPa)

A tropical depression was discovered near 14°N.,102°W., at 1800 on July 22, but it became disorganized as seen on satellite pictures the next day. Later events indicate it was splitting into two tropical cyclones, both of which were to attain tropical storm strength. The tropical storm first called lone was encountered by the KANIKAWA MARU at 2100 on July 24. That ship was buffeted by 48-kn southeasterly winds and 15-ft seas near 21°N, 107°W. The storm washed out the next day.

Tropical Storm Joyce

Tropical storm (SSHWS)
 
DurationJuly 29 – August 4
Peak intensity60 mph (95 km/h) (1-min);
1000 mbar (hPa)

A broad, flat low-pressure area persisted south of Baja California after Ione dissipated. On July 29, a small low circulation developed with a center about 120 nautical miles (220 km) south of Manzanillo. The system was given the name Joyce after winds of 40 mph (64 km/h) were reported by a ship. In a similar way to Hurricane Francesca, Tropical Storm Joyce's low level center was unclear due to a cap of cirrus clouds. Joyce reached its peak intensity on July 31 with winds of near 60 mph (97 km/h) before weakening, becoming a depression on August 1. Joyce dissipated on August 4.

Tropical Storm Kristen

Tropical storm (SSHWS)
 
DurationAugust 5 – August 8
Peak intensity50 mph (85 km/h) (1-min);
1005 mbar (hPa)

Kristen was a loosely organized storm that formed from a disturbance that was causing squalls near the Mexican coast. Tropical storm-force winds were found on August 5. Kristen was tracked by ship reports and satellite pictures. Kristen reached its peak intensity of 50 mph (80 km/h) winds on August 6. The storm dissipated on August 8 while over cold water.

Hurricane Lorraine

Category 2 hurricane (SSHWS)
 
DurationAugust 16 – August 27
Peak intensity100 mph (155 km/h) (1-min);
963 mbar (hPa)

Tropical Storm Lorraine, which formed on August 16 south of Mexico, intensified to a hurricane on the 20th. Two days later over open waters, it reached a peak of 95 mph (153 km/h) winds, but estimates from the Central Pacific Hurricane Center estimated it had winds of 115 mph (185 km/h). Without a chance to strengthen further, Lorraine weakened, finally dissipating on August 27 due to dry air.

Tropical Storm Maggie

Tropical storm (SSHWS)
 
DurationAugust 20 – August 27
Peak intensity60 mph (95 km/h) (1-min);
993 mbar (hPa)

A flat low-pressure system appeared in an area of showers to the west-southwest of hurricane Lorraine around 1800 on the 20th. The French refrigerated cargo carrier BIAFRA was buffeted by 38-kn southerly winds, with a barometer reading 1006 mbar, near 13'N, 132'W, by the soon to be named tropical storm Maggie at 0000 on the 21st. Maggie intensified slowly while moving west-northwestward at 9 kn; her maximum winds were estimated at 55 kn at 0300 on the 25th. Maggie passed about 80 mi south of the island of Hawaii on the 25th, dumping torrential rains over the big island. Rainfall amounts ranged from 10 to 15 in on the windward side of the island from the Hamuka coast to Puna and from 1 to 7 in on the leeward side. Maggie was downgraded to a tropical depression at 0900 on the 26th near 18N, 157W. A westward turn saved Hawaii from a direct hit, but Maggie still brought strong surf and heavy yet beneficial rain to the island of Hawaii. There is some evidence that the remains of Maggie redeveloped into Hurricane Dot in the Central Pacific on September 1.

Tropical Storm Norma

Tropical storm (SSHWS)
 
DurationAugust 31 – September 6
Peak intensity95 km/h (60 mph) (1-min);
988 hPa (mbar)
Main article: Tropical Storm Norma (1970)

Norma was an indirect but essential cause of a flood disaster in Arizona that became known as the "Labor Day Storm of 1970". A depression formed August 31 and rapidly intensified into a tropical storm. Moving rapidly, it headed out to sea before slowing down and weakening. Norma's circulation fed humid unstable air into a large extratropical cyclone over Arizona. As Norma dissipated, record rains fell over the state from September 4 to September 6.

The rains were deadly. There were a total of 22 deaths, including 14 from a flash flood on a creek. The damage amounted to over 1 million dollars.

Hurricane Dot

Category 1 hurricane (SSHWS)
 
DurationSeptember 1 – September 4
Peak intensity80 mph (130 km/h) (1-min);
993 mbar (hPa)

A tropical disturbance, possibly the remnants of Tropical Storm Maggie, became a tropical depression on September 1 to the northwest of Hawaii. It moved to the northwest, coming within miles of the International Date Line and Midway Island but remaining in the Central Pacific. Dot turned to the northeast, reaching tropical storm strength on September 2 and hurricane strength September 3 before being absorbed by a cold core system the next day. When Dot became a hurricane at 35° north, it became the highest latitude for a storm to reach hurricane strength east of the International Dateline. This record was soon eclipsed by Hurricane 12 of the 1975 season. A flight flown into Dot also flew into Typhoon Clara.

Tropical Storm Orlene

Tropical storm (SSHWS)
 
DurationSeptember 7 – September 9
Peak intensity65 mph (100 km/h) (1-min);
995 mbar (hPa)

65 mph (105 km/h) Tropical Storm Orlene hit Mexico in eastern Oaxaca on September 8, having maintained a northeast track for its short lifetime.

Hurricane Patricia

Category 2 hurricane (SSHWS)
 
DurationOctober 4 – October 11
Peak intensity100 mph (155 km/h) (1-min);
972 mbar (hPa)

Hurricane Patricia was a strong Category 2 hurricane with winds of 95 mph, Patricia formed on October 4 and dissipated on October 11.

Tropical Storm Rosalie

Tropical storm (SSHWS)
 
DurationOctober 21 – October 23
Peak intensity55 mph (90 km/h) (1-min);
1006 mbar (hPa)

Rosalie's existence was confirmed on October 21 by observation from a ship. Reconnaissance on the 22nd reported a central pressure of 1006 mb. After a slight regeneration on the 23rd, Rosalie began rapid dissipation, finally dissipating on the 23rd.

Tropical Storm Selma

Tropical storm (SSHWS)
 
DurationNovember 1 – November 8
Peak intensity70 mph (110 km/h) (1-min);
995 mbar (hPa)

The final storm of the season, Tropical Storm Selma, developed on November 1 to the southwest of Mexico. It meandered to the north, turning to the northeast and northwest before heading southeastward and dissipating on November 8.

Storm names

Main articles: Tropical cyclone naming, History of tropical cyclone naming, and List of historical tropical cyclone names

The following list of names was used for named storms that formed in the North Pacific Ocean east of 140°W in 1970. It was the same list used in the 1966 season, with the exception of Kristen, which replaced Kirsten. Storms were named Kristen, Norma, Orlene, Patricia, Rosalie, and Selma for the first time this season. The name Kristen was later respelled as Kirsten for 1974.

  • Adele
  • Blanca
  • Connie
  • Dolores
  • Eileen
  • Francesca
  • Gretchen
  • Helga
  • Ione
  • Joyce
  • Kristen
  • Lorraine *
  • Maggie *
  • Norma
  • Orlene
  • Patricia
  • Rosalie
  • Selma
  • Toni (unused)
  • Viviam (unused)
  • Winona (unused)

One named storm, listed below, formed in the North Pacific between 140°W and the International Date Line in 1970. At the time, storm names within this region were assigned by the Joint Typhoon Warning Center on Guam. Named storms in the table above that crossed into the area during the season are noted (*).

  • Dot

Retirement

See also: List of retired Pacific hurricane names

The name Adele was later retired without explanation. It was replaced with Aletta for the 1974 season.

Administrative changes

This is the first season that the Redwood City-based Eastern Pacific Hurricane Center started issuing advisories on tropical cyclones in the eastern north Pacific. It replaced the previous forecaster, Fleet Weather Central. Also. the Central Pacific Hurricane Center started to issue advisories on tropical cyclones in its area of responsibility this season. It replaced the Joint Hurricane Warning Center.

See also

References

  1. Climatological Data National Summary 1970
  2. ^ National Hurricane Operations Plan (PDF) (Report). Washington, D.C.: NOAA Office of the Federal Coordinator for Meteorological Services and Supporting Research. May 1970. pp. 95, 97. Retrieved February 27, 2024.
  3. ^ Padgett, Gary (July 11, 2008). "Monthly Global Tropical Cyclone Summary: November 2007 First Installment". Australian Severe Weather. Retrieved February 27, 2024.
  4. ^ "Eastern North Pacific Tropical Cyclone Name History". Atlantic Tropical Weather Center. Archived from the original on September 29, 2007. Retrieved February 27, 2024.
  5. Pao-Shin Chu; Peng Wu (2008). Climatic Atlas of Tropical Cyclone Tracks over the Central North Pacific (PDF) (Report). University of Hawaii-Manoa. Archived (PDF) from the original on October 23, 2014. Retrieved February 27, 2024.
  6. "Tropical Cyclone Naming History and Retired Names". Miami, Florida: National Hurricane Center. Retrieved February 27, 2024.

External links

Tropical cyclones of the 1970 Pacific hurricane season
1Adele TSBlanca TSConnie TDDolores TSEileen 2Francesca TSGretchen TSHelga TSIone Two TSIone One TSJoyce TSKristen 2Lorraine TSMaggie TSNorma 1Dot TSOrlene 2Patricia TSRosalie TSSelma
1970–1979 Pacific hurricane seasons
Tropical cyclones in 1970
Cyclones
Hurricanes
Typhoons
Non-seasonal lists
Categories: