Snoqualmie Pass, Washington buried in snow; 85 inches on the ground

Cliff Mass
Cliff Mass Weather Blog
Thu, 24 Dec 2015 18:04 UTC

© Cliff Mass Weather Blog

Last year, Snoqualmie Pass had very little snow and the ski areas remained shut for most of the winter.

This year Snoqualmie is being BURIED IN SNOW.

Every day at 6 AM, Washington Department of Transportation measures snow depth in the pass. Here are the latest numbers: 26 inches of snow between 6 AM Monday and 6 AM Tuesday, with 85 inches on the ground. An increase of 50 inches in 5 days. To quote Darth Vader: Impressive, Most Impressive.

The Wednesday report shows another 11 inches of new snow, but compaction resulted in only a 1 inch increase in depth.

© WSDOT

The pass has been closed several times during the past few days, with chains often required. So far this year over 12 feet of snow has fallen in Snoqualmie, eclipsing the total snowfall of the entire last year.

But it is not over. Last night, another frontal system moved through, bringing a surge of heavy snow. Here is the forecast of 72-hour snow total for the region (a circle indicates the location of Snoqualmie Pass). Another 2-3 feet!

The freezing level is quite low now and during the next few days, with the associated snow level dipping to around 1000 ft, with mixed snow getting down to 500-1000 ft at times. Don't be surprised to see a few flakes at sea level, particularly over N.W. Washington.

© Cliff Mass

But why so much snow?

The reason is that the atmospheric has been stuck in a configuration that has been ideal for central Cascade snow (and very favorable for heavy rain over Oregon). Here is the upper level (500 hPa) forecast for Tuesday at 7 PM. The lines are height (like pressure) and winds are strongest when the lines are close together (that is where the jet stream is located). The jet stream is oriented NW-SE with the axis crossing Oregon and northern CA. We are on the north (cold) side of the jet stream and there is a trough just offshore.

So we are cool, with disturbances rippling along the northern side of the jet stream. Good for Cascade snow.