Winter Weather in Copper River Basin, Alaska

Numerous reports of accumulating snowfall were relayed by the Alaska Department of Transportation, most of which fell from about 11 PM 5/30 to the early morning hours of 5/31. Around 6 inches fell over Glennallen, with mostly 1-2 inches of slush reported farther south and west. Heavier snowfall was reported along the Tok Cutoff and northern Richardson Highway, including up to 10 inches in Paxson.

A very cool air mass settling into the Copper Basin near a deep upper level trough centered over Mainland Alaska was able to interact favorably with a series of weak upper shortwaves that moved into the Copper Basin from the Yukon to produce widespread snowfall. This was able to occur near the diurnal minimum surface temperatures for several hours during the late evening of 5/30 to the early morning of 5/31. Most of the higher amounts fell at higher elevations near the Alaska Range, including up to 10 inches near Paxson.