Winter Weather — Kuskokwim Delta, Alaska

2023-01-26 to 2023-01-28 · Kuskokwim Delta, Alaska

Event narrative

Areas around Bethel began seeing snow mix with freezing around 5-6 PM 1/27 with clear evidence if ice buildup on the Napakiak webcam cover facing into the wind, and similarly at Bethel slightly later in the evening. Freezing rain was also reported at the Bethel ASOS at 9 PM 1/27. Temperatures warmed above freezing near 12 AM 1/28 and changed the freezing rain and snow mix to all rain.

Wider weather episode

A classic setup for freezing rain across portion of Southwest Alaska took shape beginning on the afternoon of 1/27 as a warm front working north over the eastern Bering Sea and up the Alaska Peninsula slowly progressed north into a retreating Arctic air mass initially in place across most land areas of Southwest. Temperatures at the surface were mainly at or below 15 Fahrenheit to start off the early morning across much of Bristol Bay and interior parts of the Kuskokwim River Valley. Farther south, the warm front began to work north up along the Alaska Peninsula, pushing in southeast winds and temperatures in the mid 30s to low 40s in its wake.

The shallow cold air mass in place farther north with north to northeast winds holding on for most of the day at the surface allowed for a significant frontal overrunning event to occur, with a warm nose of air above freezing streaming out ahead of the surface warm front. An inversion only a few 100 to few 1000 feet thick below the warm layer allowed for several hours of melting snow to fall as freezing rain at ground level in a number of favored locations across Bristol Bay. About 0.25 inches of ice accretion was recorded at King Salmon during the morning hours of 1/27 before the front pushed through in the early afternoon and allowed temperatures at ground level to warm above freezing.

Farther north, northerly winds continued to dam cold air into the Kuskokwim Mountains for much longer, leading to many hours of accumulating freezing rain for Dillingham and Clark's Point, where nearly 0.5 inches of icing was recorded before the front finally pushed through and warmed surface temperatures above freezing during the evening hours of 1/27.

As the front continued to progress north into the Kuskokwim Delta, it began to accelerate, resulting in a faster transition from snow, to freezing rain, then to rain for areas between Quinhagak and Bethel as winds turned from northeast to southerly and as warm air began to flood in at the surface. This resulted in much lighter ice accretion less than 0.1 inches and lower impacts for areas in and around Bethel.

Source: NOAA Storm Events Database, event_id 1099938. Narrative written by the NWS forecast office that issued the report.