The Great Eastern Washington Melt Out

Eastern Washington built up an above-average low-elevation snowpack at low levels in February and early March as a result of the extraordinary persistence of below- normal temperatures.

But temperatures have been rapidly warming the past week and the snow is melting fast.  You can appreciate the sudden warm up at Pasco in the central Columbia Basin from the figure below.  A progressive warming the last few day to highs that are even above normal.

But to appreciate the snow melt on a visceral level, let me show you a series of high-resolution MODIS satellite images.

March 13th--the Columbia Basin is snowbound

 Two days later, March 15th-- the snowpack is beginning to melt, with brown areas showing.

 By March 17th, the holes are really enlarging.

By March 20, broad areas are snow-free.

 And today, March 21st, most of the snow cover is gone at lower elevations.

The National Weather Service is warning about some very minor localized small stream flooding...nothing much to worry about.  But the snow cover and cold temperatures have left the soil temperatures quite cold in the Columbia Basin.

Here are the soil temperatures 8 inches below the surface from the WSU Agweather website.  Many are above 50F in western WA, much fewer in eastern WA, where some are still in the 30sF.  The agricultural season will be slow starting east of the Cascades.