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Sea Ice Outlook for Western and Arctic Alaskan Coastal Waters 

National Weather Service Anchorage Alaska 1038 AM AKST Thursday 27 

February 2025



Updated Cook Inlet Break-Up



...FEBRUARY 2025 MONTHLY SEA ICE OUTLOOK...



January ended with the Bering Sea maximum ice extent for this 

season, so far, with the ice edge having reached St. Matthew Island. 

However, February had other plans in store with a long period of 

southerly and southeasterly winds retreating the ice edge back to 

the north, nearly to St. Lawrence Island.  A very large polynya had 

formed from the Yukon Delta southward toward Etolin Strait. Most of 

the ice around the Kuskokwim Delta had melted or compacted up 

against the shorefast ice of the coast. Bristol Bay has continued to 

struggle to maintain any ice at all with only a pocket of marginal 

ice near the Nushagak Peninsula. 



However, in the last half of the month, the storm track shifted and 

brought the ice edge back southward from St. Matthew Island to the 

Kuskokwim Delta. Ice in Cook Inlet recovered from near complete 

annihilation in January to the greatest extent for the 2024-2025 

season.



Finding analog years was difficult this year with 2019 being the 

closest year and 2016 fairly close as well. There were only two 

years in the last 25 that had less ice in February than this year. 

However, complicating matters is that the late February advance of 

the ice pack/edge to St. Matthew Island puts it on par with more 

recent years.



As we look forward through the end of “winter” and into the very 

beginning of break-up season, weak La Nina conditions are expected 

to shift toward ENSO-neutral conditions which should favor general 

climatology of the last 10 years.  Despite the ice edge recovering 

recently, the ice will not have had much time to thicken which will 

likely favor earlier than normal break up across much of the Bering 

Sea, but likely closer to normal for the Chukchi and Beaufort Seas. 



...FREEZE-UP OUTLOOK FOR THE BERING SEA...



Any further freeze-up past what has already been experienced this 

year in the Bering Sea will require a long-duration arctic air 

outbreak and northerly winds. March and April’s increasing sun 

angles/temperatures and climatologically dryer conditions would 

favor freeze-up nearing an end. 



The ice edge makes it to Saint Paul Island around 50 percent of the 

years on record, and is usually late in the ice season. That remains 

incredibly unlikely, barring the long duration, northerly wind 

arctic air outbreak, and even then sea surface temperatures would 

have to cool substantially for ice to remain. 



For the Alaska Peninsula, sea ice growth is not expected for the 

remainder of the season.



...FREEZE-UP OUTLOOK FOR COOK INLET...



The period from January 1, 2025 through February 24, 2025 was the 

fifth warmest on record at Anchorage since 2000, with the 2001, 

2013, 2014 periods having very similar average temperatures. The 

current extent of ice is the most we’ve seen all season, reaching 

around both sides of Kalgin Island. However, there are many large 

areas of open water or marginal ice, and very little pack ice left. 

While longer term guidance is suggesting below normal temperatures 

in mid-March, sea ice growth becomes very difficult this time of 

year due to increasing sun angles and sea surface temperatures that 

never get below freezing.  The overall extent is not expected to 

increase for the rest of the year, and we have likely peaked for 

both thickness and extent.  



...BREAK-UP OUTLOOK FOR COOK INLET...



With a low sea ice extent expected for the remainder of the freeze-

up season, what sea ice does form will be quicker to melt than 

average. Break-up dates listed here are largely weighted toward the 

winters of 2000-2001, 2012-2013 and 2013-2014. 



South of Kalgin Island will be ice free or open by the second week 

of March.



South of the Forelands is expected to be ice free or open by the 

third week of March.



For the Forelands to Fire Island, three tenths conditions and ice 

free conditions are expected by the third week of March.



Turnagain Arm is expected to be ice free during the last week of 

March.



Cook Inlet is expected to be sea ice free for the season by the end 

of March.



...BREAK-UP OUTLOOK FOR THE BERING SEA...



The sea ice extent within Bristol Bay is expected to continue to be 

variable throughout the remainder of the winter season. Sea ice is 

expected to remain below three tenths concentration and will be sea 

ice free for the season by the first week of April.



Within Kuskokwim Bay, sea ice is expected to no longer be shorefast 

by mid-April. Sea ice concentration is expected to reach 3 tenths 

and become sea ice free by the end of April.



Etolin Strait sea ice is expected to reach three tenths during the 

second half of April and be sea ice free by the last week of April 

or first week of May.



For Etolin Strait to Cape Romanzof, ice will no longer be shorefast 

and sea ice concentration is expected to reach three-tenths coverage 

during the second half of April. Ice free conditions are expected by 

the end of April or early May.



For Cape Romanzof to Nunam Iqua, ice is no longer expected to be 

shorefast during the first half of May. Three tenths coverage is 

expected during the second half of May. Ice free conditions are 

expected by the end of May.



For Nunam Iqua to Unalakleet, ice is no longer expected to be 

shorefast during the second half of May. Three-tenths concentration 

is expected by the end of May. Ice free or open conditions are 

possible by the end of May, but more likely at the beginning of 

June. 



For Shaktoolik, three-tenths coverage and ice free conditions are 

expected during the first half of May.



For Norton Bay, ice is no longer expected to be shorefast during 

late May. Three-tenths of ice is also expected during late May. Ice 

free conditions are possible in late May but more likely in June.



For Golovin Bay ice is no longer expected to be shorefast during 

late May. Three-tenths of ice is possible during late May. Ice free 

conditions are not expected until June.



For the Nome area, ice is no longer expected to be shorefast by 

early May. Three-tenths coverage of ice is expected around mid-May. 

Ice free conditions are expected by the end of May. 



For Norton Sound, three-tenths coverage is expected during the 

second half of May. Ice free conditions are possible by the end of 

May, but more likely in early June.



For Port Clarence, ice could no longer be shorefast by the end of 

May but is more likely into June.

For the Bering Sea south of 60N, ice free conditions are expected 

during the first half of May.



...BREAK-UP OUTLOOK FOR THE CHUKCHI SEA...



For Wales to Espenberg, ice is no longer expected to be shorefast 

during late-May.



For Cape Krusenstern to Point Hope, ice is no longer expected to be 

shorefast during the second half of May. 



$$ 

Lawson