Winter Weather — Copper River Basin, Alaska

2023-01-24 to 2023-01-25 · Copper River Basin, Alaska

Event narrative

Alaska Department of Transportation reported a myriad of mixed precipitation starting out as snow, then mostly transitioning to rain as warm air above freezing filtered into valleys across the Copper River Basin from the south with time between 1/24 and 1/25. Most locations did not receive significant snowfall or rainfall totals (no more than 6-7 inches of new snowfall prior to transition). Tazlina reported a brief period of freezing rain before switching over from snow to all rain during at around 5 AM 1/25.

Wider weather episode

A push of deep warm, southerly flow aloft combined with synoptic frontal lift over-top air starting out below freezing at ground level combined together to produce a mess of mixed precipitation types across much of Southcentral Alaska between 1/22 and 1/25. Warm air with southerly winds gradually was able to work north and change wet snow over to rain as it filtered into interior valleys, with some mix with freezing rain observed briefly during the transition phase in a couple locations. While precipitation amounts were generally light, aside from over a foot of snowfall observed in parts of the Susitna Valley, the sudden thaw and rain on top of snow and cold ground resulted in significant disruptions to travel and daily life for many residents across the region.

Source: NOAA Storm Events Database, event_id 1099832. Narrative written by the NWS forecast office that issued the report.