Winter Weather — Copper River Basin, Alaska

2023-10-05 to 2023-10-06 · Copper River Basin, Alaska

Event narrative

On the morning of 10/6, NWS Anchorage made calls out to the Tazlina Department of Transportation and Edgerton Department of Transportation to assess conditions after a prolonged period of mixed precipitation. Both locations reported that freezing rain started around 2 pm AKST on 10/5 and persisted well into the night. Tazlina estimated 1/2 inch of ice/sleet accumulation on the Richardson Highway. An estimated 1/4 inch to 1/2 inch of ice/sleet accumulation was reported on Edgerton Highway.

Wider weather episode

Another early season winter system impacted parts of the southern Copper River Basin on October 5th as a low curving northwest across the Gulf interacted with a cold air mass in place over the interior valleys across Southcentral Alaska. Warm air overrunning this air mass resulted in a temperature profile favorable for freezing rain and sleet as precipitation overspread the Copper River Basin, with numerous reports of slush, sleet and ice buildup along parts of the Glenn Highway and southern half of the Richardson Highway through the night of 10/5. The worst conditions and ice/sleet accumulations were reported along the Richardson Highway and Edgerton Highway north of Thompson Pass, where around 1/4 to 1/2 inches of ice and sleet accumulation occurred.

Source: NOAA Storm Events Database, event_id 1133678. Narrative written by the NWS forecast office that issued the report.