Blizzard — Kenai Peninsula, Alaska

2023-11-07 to 2023-11-08 · Kenai Peninsula, Alaska

Event narrative

Gusty north winds knocked down trees and caused power outages with winds gusting to 40 mph along with falling/blowing snow between 11 PM 11/7 through 3AM 11/8. Power outages would continue to affect residents of the area through 11/9/2023.

Wider weather episode

A high impact, heavy snowfall event unfolded across large portions of Southcentral Alaska between 11/8 and 11/9, with the most intense and prolonged snowfall recorded across the mountain passes near Prince William Sound and out towards much of the Kenai Peninsula, Matanuska Valley and greater Anchorage area.

The setup for this event was very complex, unique and incredibly challenging from a forecast perspective. A deep, negatively tilted upper trough stalled out between Southwest Alaska and the Alaska Gulf as a front and atmospheric river surged out ahead of this feature into the Gulf Coast, allowing very high moisture to stream north and west along it into Prince William Sound. A small but very intense low spun up along this frontal zone, moving northwest into Prince William Sound late on 11/8 and continued north into the Susitna Valley as it dissipated by the afternoon of 11/9. An axis of deep lift and moisture near the nose of the atmospheric river and to the east of the low as it tracked north and west remained focused between the Prince William Sound and Mat-Su Valleys for several hours, resulting in several feet of heavy, intense snowfall across the Chugach Mountains and between 12 and 36 inches of new snowfall from portions of the Kenai Peninsula out to Anchorage and across the Matanuska Valley.

Some numerical model guidance leading up to this event performed very poorly, projecting a much more west track for the low as it crossed the mountains towards Susitna Valley. This scenario would have allowed much warmer air to flood into the Anchorage and Matanuska Valley, and would have also resulted in a transition over to rain during the highest intensity of precipitation. This never materialized, and the bulk of precipitation during the event fell as snow for most locations.

Source: NOAA Storm Events Database, event_id 1140745. Narrative written by the NWS forecast office that issued the report.