Winter Storm — Copper River Basin, Alaska

2021-11-19 to 2021-11-20 · Copper River Basin, Alaska

Event narrative

Webcams through the FAA showed fairly low visibilities through Thompson Pass as a result of the falling snow and strong gusty winds. Conditions remained unchanged for hours resulting in treacherous and dangerous travel conditions through Thompson Pass from the afternoon of the 19th into the early morning of the 20th.

Wider weather episode

A storm system in the Gulf of Alaska sent a front northward onshore southern Alaska. The moisture associated with the front moving northward and a tight pressure gradient across the southern Copper River Basin resulted in strong gusty winds along with falling snow causing significant blowing snow conditions, especially through Thompson Pass. This resulted in very low visibilities to a half mile or less throughout the duration of the event.

Source: NOAA Storm Events Database, event_id 1001867. Narrative written by the NWS forecast office that issued the report.