Record Rain and Snow

Fairbanks schools and borough offices are closed for the second day today, as record-breaking rain and wet snow has produced difficult travel conditions in the area.  The airport's two-day liquid-equivalent precipitation total of 2.28" is within the top 10 for any time of year (1930-present), and of course most of the heaviest precipitation events occur in the warm season in Fairbanks.  Only two cold season events have seen higher two-day totals: the Christmas storm of 2021 (2.45", blog post here) and January 19-20, 1937 (which was actually a three-day event totaling 3.21"). 

More superlatives: yesterday's calendar day precipitation total of 1.99" is the third largest of any day since 1930 in Fairbanks, the only wetter days being July 27, 2003, and August 12, 1967 (the great Fairbanks flood).  And according to Rick Thoman, the peak 24-hour total (Sunday evening through Monday evening) of 2.07" is the highest on record for the cold season, and the first to exceed 2".  The previous cold season record for 24 hours was 1.93" in the 2021 storm, and before that 1.84" in 1937.

Higher amounts were reported elsewhere: a CoCoRaHS site near the airport measured 2.96" in the two days, and the Keystone Ridge site came in at 3.27".

At least half of the precipitation fell as plain rain, according to the airport ASOS data, and owing to temperatures persistently below 20°F late last week, the cold ground led to lots of ice formation.  There's a window for some thaw today, but temperatures will drop back below freezing tonight and stay there, so some of that ice is going to be around all winter, unfortunately.  It's a theme we've seen repeatedly from winter rain events in Fairbanks in recent years.

Here's a snapshot of the atmosphere's vertical profile at 4pm AKDT yesterday; it was still raining at the airport, but rain had switched back to snow on Keystone Ridge:

Check out the wind speeds aloft: over 150 mph at 34,000 feet.  The southwesterly flow direction through much of the lower and middle atmosphere is what brought the moisture into the central interior without it being squeezed out by the Alaska Range to the south.

As for storm impacts elsewhere in Alaska, the west coast has been very windy, strong winds affected south-central areas yesterday, and Bering Sea coastal flooding has undoubtedly been significant, but I haven't seen detailed reports yet.

Far to the west over Chukotka's Arctic coast, the storm's central pressure bottomed out at around 956 mb according to Environment Canada.  As noted in Friday's post, this is very likely an October record for that location, but we'll have to wait a few days for the ERA5 data to be sure.  Here's the surface analysis from 4am AKDT yesterday.