The 2011–12 Alaska hurricane season began on November 1, 2011 and will end on March 31, 2012, with most tropical cyclones forming in December, January and February. However, any tropical cyclone that forms between July 1, 2011 and June 30, 2012 will be part of the 2011–12 season. This is the first season in which hurricanes have formed in the Alaskan basin. The Alaska Hurricane Center (AHC) in Anchorage issues advisories when a storm forms in between 120°W, 45°N and 150°E, 45°N. Storms are given the identifiers 'K' (for example, Tropical Depression 3K).
On November 3, a large area of low pressure became organized enough to become Tropical Storm Abby. Abby strengthened rapidly to near hurricane status, but on November 8 due to interacting with land, Abby weakened and dissipated the next day.
One man has been reported missing after being swept away from Kodiak, AK. Many meteorologists have said that the storm looked more like an extratropical system than a tropical cyclone.
A large area of thunderstorms became Tropical Depression Two on November 7. These thunderstorms did not develop a low-level circulation until at least November 8. The depression began to develop a cold front and was considered post-tropical on November 9.
The storm did not affect land, meaning that nobody died from this storm, but there was $60 in damage.
The remnants of a typhoon in the Western Pacific became more organized as it entered the Gulf of Alaska and was designated Tropical Depression 3K. The system rapidly deepened as it moved into above normal sea temperatures, and became a tropical storm. On November 13, the AHC began issuing hurricane warnings for the Alaska Panhandle. It strengthened into a hurricane a few hours later. Sea surface temperatures in the Gulf of Alaska were almost 5C above average, this lead to Bertha strengthening into a Category 2 hurricane. Despite strong wind shear, Bertha strengthened into a major hurricane. On November 15, Bertha strengthened into a Category 4 hurricane. It began weakening shortly after and weakened to a Category 1 hurricane two days later. As it made landfall near Anchorage, it weakened to a tropical depression and then dissipated.
A large area of cloud and thunderstorms moved off the coast of Russia, it then organized and became a tropical depression on November 14. It rapidly intensified and became Tropical Storm Claudette later that day. Additional strengthening occurred on November 15, with Claudette becoming the seasons 2nd hurricane. It then made landfall on the southern tip of the Alaska Peninsula, and weakened to a tropical storm shortly afterwards. After entering the sea once again, Claudette strengthened into a Category 1 hurricane once again on November 16. It weakened to a tropical storm again, but strengthened back to a hurricane shortly after. Claudette began moving very fast towards the west-northwest at 82 mph and weakened back to a tropical storm. Wind shear began to rip the system apart and Claudette dissipated on November 19.
The remnants of East Pacific Hurricane Kenneth, a strong Category 5 storm, moved into the Alaska basin as a tropical storm and was renamed Daniel on November 16. After interacting with land early the next morning, it became post-tropical.
However on November 18, it organized once again and became a tropical storm. It slowly moved south-westwards and on November 21, it moved into the Central Pacific basin.
A tropical wave that traveled through the Atlantic and the eastern Pacific, without development, formed during the evening of November 18. It continued to strengthen and during the early hours of November 19, it became Tropical Storm Estelle. Rapid strengthening occurred during the late hours of November 19, with Estelle becoming a Category 2 hurricane. More strengthening occurred the next day, and Estelle became a major hurricane. On November 23, it strengthened into a dangerous Category 5 hurricane. It later weakened back to a Category 4 hurricane as it neared landfall. As it re-entered sea again, it strengthened back into a Category 2 hurricane. Estelle began interacting with a cold front which then caused it to rapidly weaken. Estelle became post-tropical during the afternoon hours of November 26.
A non-tropical low developed into a subtropical depression in the early hours of November 28. However, the next day it gained tropical characteristics. The depression began weakening shortly after and became post-tropical on November 30. The remnants of the depression became a violent Aleutian Low and killed 40 people.
An extratropical cyclone formed on November 29 and on December 2, gained tropical characteristics. It was then classified as Tropical Storm Falcon. More strengthening occurred on December 5 when the storm was upgraded to a hurricane. However, only hours later, strong wind shear caused the system to rip apart and Falcon later dissipated on December 5.