Dust on Snow?

Over the past few years, there have been a number of insidious dust storms that have swept up southern Utah and inundated the Salt Lake Valley with poor air quality and made a mess of our spring skiing.

Tax Day Dust Storm, April 15, 2002

Snow with dust layering, Alta, UT, Spring 2009
(Photo: T. Painter)

Not only does the dust make for ugly snow with poor glide, it increases the absorption of radiation from the sun, leading to "mushier" snow on spring days, an earlier loss of snow cover, and a shorter ski season for diehards who just don't know to quit when the powder stops flying.

Thusfar this year we have escaped the wrath of major dust storms, but that could change this weekend.  The NAM model is cranking up the southerly and southwesterly flow on Saturday afternoon.

1800 UTC 17 Mar initialized NAM forecast valid 2100 UTC
(3 PM MDT) 19 Mar 2011.

These winds are strong enough for dust emission and transport from areas where the land surface has dried and been disturbed.  In past events, dust sources have included areas around the Sevier Lake bed and the Milford Flat fire scar.

MODIS dust identification imagery with possible dust plumes
indicated in pink.  Milford Flat Fire denotes area scared by
fire that has become a dust emissions source for northern Utah
(Courtesy Naval Research Lab)

At issue is if the land-surface to our south is ready to produce dust.  During the last major southerly wind storm it wasn't, but perhaps now that we're creeping into spring it is?  We'll see this weekend.