High Wind — Matanuska Valley, Alaska

2022-01-01 to 2022-01-04 · Matanuska Valley, Alaska

Event narrative

Of significance was the longevity and extremes recorded during the event. First, the strongest winds recorded were at the Palmer Airport with a peak wind gust of 88 mph at 5:36 PM January 2nd, and a gust to 91 mph at the Glenn-Parks Highway Interchange at about the same time. This rivals the strongest gusts reached at the Palmer Airport since recording began in 1972, becoming the 5th strongest wind gust recorded at the Palmer Airport, though the four strongest gusts only occurred over two separate days, December 23, 1996 and January 17, 2005, ranging between 90 and 112 mph (see graph below). The Wasilla Airport peaked at 74 mph on January 2nd at 10:16 PM.

Second, the longevity of the event was pronounced. Not only was there about 40 hours of hurricane force winds (74 mph or greater) noted at the Palmer Airport, but there were about 51 hours of wind gusts 50 mph or greater between January 1st and 3rd. Taking a regional perspective and including Anchorage in the picture, this Bora Wind event ranks 5th for longevity since records began, though is likely the strongest wind event associated with a Bora Windstorm for Palmer on record.

The final aspect of note was the extreme cold associated with the event and longevity to which the cold lingered. While temperatures dropped into the single digits by January 2nd, temperatures dropped below zero January 4th and remained frigid through January 7th, before increasing back into the teens. This proved to be quite impactful as winds took down many power lines, causing difficulties for many in the extreme cold and causing pipes and water mains to break.

We received reports of blown-over trucks, toppled Cessna airplanes at the Palmer Airport, downed trees and power lines (with power outages across the valley causing pipes to burst and people to seek shelter elsewhere due to the prolonged cold), windows broken, cars damaged due to flying debris, and siding ripped off homes and businesses. Emergency Management reported multiple CO poisoning calls, requests to be transported to the hospital, along with cases of frostbite.

Links to news coverage: https://www.adn.com/alaska-news/mat-su/2022/01/03/in-pictures-windstorm-batters-palmer-and-wasilla/, https://www.adn.com/alaska-news/weather/2022/01/02/thousands-without-power-as-heavy-winds-hit-southcentral-alaska/, https://www.alaskasnewssource.com/2022/01/01/power-outages-occurring-across-southcentral/?utm_source=twitter&utm_medium=social&utm_campaign=snd&utm_content=ktuu, and https://www.alaskasnewssource.com/2022/01/02/strong-winds-affecting-power-travel-mat-su/?fbclid=IwAR1IQvdqJGGfv0jw85F0FUqprDwQefUzrp9dN3H_O8AelpHyu7S8mv3q4qY.

The Executive Weather Summary can be found here: https://docs.google.com/document/d/1oYQb2EPRyj5bM-rkA56RKFD-nsjs5EHs96BE24bpyMo/edit?usp=sharing.

Wider weather episode

A ridge of high pressure aloft shifted northeast out of the western Bering Sea on December 31, 2021, strengthening over northern Alaska January 1-3, 2022. The development of this ridge, caused an extremely cold air mass over northern Alaska to dive southward across southern Alaska and into the Gulf of Alaska. This is an ideal setup for a Bora wind event over Southcentral Alaska, whereby very cold air is forced over the Alaska Range and southward across Southcentral Alaska, leading to widespread strong and gusty winds and cold temperatures. This set-up allowed several noteworthy details to occur:

1. Very cold air, bottoming out at about -31F to -40F, moved over the Alaska Range and into the Copper River Basin at about 3kft above ground, on January 2nd. Surface temperatures dropped to single digits on the 2nd, and below zero on January 4th.

2. Amplified pressure differentiations developed between the northeast Gulf and northern Alaska. The strengthening surface low over the Gulf dropped to about 972 mb, while an extremely strong surface high topped out around 1052 mb on January 2nd. This created extremely tight pressure gradients between the northern Alaska high and the Gulf low, especially over Southcentral Alaska. This led to the development of strong winds from the northeast over the period, accelerating through the Matanuska Valley.

3. The presence of both thermal and pressure gradients combined to create much stronger winds than would otherwise be observed if standing alone.

While the region hardest hit by this high wind and cold weather event was along the Matanuska-Susitna Valley, many other locations across southcentral were also impacted by frigid temperatures and windy conditions.

Source: NOAA Storm Events Database, event_id 1018094. Narrative written by the NWS forecast office that issued the report.