The Spada Lake Anomaly

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There is a precipitation anomaly around here that is rarely discussed.
In many ways, it is the anti-Sequim, anti-rainshadow.
A place of extraordinary precipitation near Puget Sound.

I am talking about the Spada Lake anomaly.

Spada Lake
 Let us begin by talking about the mountain foothills, east and northeast of Everett, much of it in the Sultan River watershed.  On the map below,  Spada Lake is labeled and the red A is at Verlot.

Spada Lake is circled
During the 48 hrs ending Wednesday at 8 AM, Spada Lake got over TEN inches of rain (10.47 inches)--no other regional station was close.  On average, the surrounding Sultan River basin gets about 165 inches a year--almost identical to the Olympic Peninsula Hoh rain forest!  And consider the typical annual precipitation of nearby locations on the Mountain Loop Highway:

Verlot Ranger Station (elevation 980 ft):  135.5 inches
Big Four Ice Caves (elevation 1750 ft):  142.5 inches

Here are some gee-whiz numbers for Spada Lake precipitation:
Peak annual - 224 inches (1990-91)
Highest Month – 51 inches (November, 1990)
Wettest Day – 13 inches  (November 11, 1990)

Folks, this is a REALLY wet place.  In contrast, nearby Everett, gets only about 37 inches a year.  The city of Everett has a reservoir there and let me assure you, they don't have a problem of lack of water.  And will not have one under any imaginable circumstance.  Official precipitation maps (see below) suggest the effect (although this map has its issue).
A wet region extends from Spada Lake up through Verlot and beyond to Mt. Baker.  Why?  Take a look at the larger terrain map of the region (below)    You notice the Cascades takes a cant to the left from Everett northward.   Strong southerly to southwesterly flow, which is very prevalent around here in winter, moves up Puget Sound and then slams into this blocking terrain.   This forces the air to rise, which leads to clouds and precipitation.  Mount Baker enjoys some of this effect, and that explains why it holds the record for more annual snowfall of any location in the world.  As in real estate, location is everything.

 Although the winds were westerly and northwesterly at higher levels, southwesterly winds WERE observed during that period.   To illustrate this, here are the winds from the Seattle profiler during 24-h of the events:

 PS:  For the lowland snow lovers in the crowd, there appears to be an enhanced chance of some light snow in some lowland locations on Sunday.....more on that tomorrow.  No big storm though. And the long-term pattern is excellent for mountain snows... classic La Nina year late season snowfall!  Don't put your skis away!

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