Wednesday, September 30, 2015

Historic Snow

More to come on this event, but yesterday's official snowfall of 11.2" in Fairbanks is the greatest calendar day snowfall on record for September (1930-present); the previous record was 7.8" on September 13, 1992.  The storm total of 11.9" (through midnight last night) is the second greatest, as the mid-September event of 1992 brought 17.4" over 5 days.

The past week has brought a total of 18.6" of snow in Fairbanks (through midnight).  It's remarkable to consider that only 15 winters (1930-31 through 2014-15) have seen more snow in a single week - see the chart below.  If 1.5 more inches fall before this event is over, which seems possible, then only 11 winters will have seen more snow in a week.  Only 1 winter in the last 15 brought such an onslaught of snow in one week (2010-11).

Some more factoids: a snow depth of 11" (last night's reading) isn't usually reached in Fairbanks until December 8.  In nearly a quarter of years it isn't reached until after the New Year (for example, the winters of 2000-01 through 2002-03, and 2005-06 through 2007-08), and in 1940-41 and 1952-53 the entire winter had less snow on the ground.

As my post the other day illustrated, this depth of snow has never melted off completely before spring.  However, the forecast looks very warm, and so it seems the odds still favor the reappearance of bare ground before the permanent snow cover is established in Fairbanks.

Here's a loop of infrared satellite images showing the evolution of the deep cloud cover during the period of heaviest snowfall in Fairbanks yesterday.  Blue colors show cold, high cloud tops, and orange indicates a warm ocean or land surface; note the warmth in the Yukon Territory (it was 66°F in Carmacks).

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