October 1: 12°F Ambler
October 2: 8°F Bettles
October 3: 5°F Wiseman, 2°F Kanuti NWR RAWS
Temperatures of 14°F (-10°C) or lower were particularly widespread yesterday morning, and a few sub-zero readings showed up on the North Slope:
Snow cover is widespread on the hills and - judging from webcam photos - much of the southeastern interior, but the western interior is mostly snow-free to the south of the Yukon River. Here's a satellite image from yesterday afternoon, with blue color enhancement showing where the algorithm picked up snow cover:
How about this for late autumn views in the northeastern interior settlement of Arctic Village this morning:
Light snow fell in Fairbanks for about 10 hours on Thursday, but the measured accumulation was only 0.1", and that melted out rather quickly with a high temperature of 36°F later in the day. The following day - October 2 - was chilly, with a high temperature of only 33°F; but it's not unheard-of to get daily high temperatures below freezing by this time of year.
It's interesting to look at how the calendar affects the probability that snow on the ground will melt out before further snow arrives in Fairbanks - consider the chart below (click to enlarge).
At the beginning of October there is still about an 80% chance that a 1-inch snow cover will disappear at some point in the subsequent days or weeks, but this drops to 50% on October 10 and only 20% on October 20.
The probability of a 3-inch snow cover melting out in Fairbanks drops even more rapidly in early October: from over 60% in the first few days of the month to 25% by October 10. So even a relatively heavy snowfall at the very beginning of October is not safe from subsequent melting; but you only have to wait a week or so for much better odds of the snowpack remaining through winter.
As for a 6-inch snow depth, there have only been 3 years in which such a substantial snow depth melted out in late autumn: 1936, 1972, and 2015. In 1936, 6 inches fell on the 17th of October but disappeared by the 26th, and in 1972, temperatures above 50°F in mid-October melted an apparently robust early October snowpack. The 2015 meltout occurred following record snow in late September, and snow didn't return until October 29th. The blog archives make for interesting reading, e.g.
Of course no mention of early winter snowpack loss would be complete without mentioning the "brown Christmas" of 1934, following the great early-December chinook - unquestionably one of the most extreme weather events in the recorded climate history of Fairbanks.
No comments:
Post a Comment