Disappearing act

Posted at 1:26 PM on March 26, 2008 by Craig Edwards (1 Comments)

The warmth of the March sun is accelerating disappearing act of the season long snow cover. South facing slopes have the benefit of more direct sunlight and thus are the first to expose the leftovers from autumn.

A couple of things are happening with the fading compressed snow pack. Melting is beginning to transport the moisture over the frost covered soil. Water is trickling into the channels and under the ice of ponds and creeks. A percentage of the snow is transitioning straight from ice to vapor, known as sublimation. Some of the snow decaying to liquid is evaporating into the lower atmosphere, aided by a rush of wind. All of these physical processes are important considerations in the accuracy of forecasting river crests from spring snow melt.

River forecast for southern Minnesota

Remember the official temperature is recorded in the shade, so a daytime stroll in direct sunshine can make the ambient air temperature feel darn right delightful.

Speaking of disappearing....the potential for a significant snowfall in proximity to the southern suburbs of Minneapolis/St. Paul is lessening with each computer model run.

Graphical snowfall potential
CE

Comments (1)

South facing slopes have the benefit of more direct sunlight and thus are the first to expose the leftovers from autumn.

Yup. Our driveway and front lawn face south and are slightly sloped down toward the street. Before last week's snowfall, our front yard was nearly bare, while our back yard, in the shadow of our house, still has lots.

And a big reason I love the March sun is that after the past weekend's "aftershocks" from the big Thursday storm, I didn't have to shovel my driveway at all. The sun melted it all.

Posted by Chris B. Critter | March 26, 2008 3:15 PM

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