For about 24 hours starting the evening of February 18th, the snow blew hard across western Colorado leaving up to 8 inches in southwestern parts of the state, according to the National Weather Service. Wind speeds at one point reached 115 miles per hour at high elevations. While the storm brought needed moisture, Jeff Derry of The Center for Snow & Avalanche Studies in Silverton, noticed that it carried something else besides snow—dust.
Derry said that as the wind and snow were blowing sideways you could see dust within the snow and on the ground and collecting in eddies. It was very noticeable while the storm was happening, and even saw the dust blowing on sidewalks. Two of his employees noticed the dust while driving some miles away on Red Mountain Pass. It was also noticed as far away as Aspen Mountain and Beaver Creek. The dust is swept up from the Colorado Plateau, an area in southern Utah and northern Arizona, which Derry said is the main source of particulates for the state of Colorado.
A recent study from the University of Colorado points out that dust on and in snow may be more important than temperature in determining when snowmelt will reach rivers and reservoirs. The dust collects heat from the sun and causes snow to melt faster and even earlier in the runoff season.
That can be a problem for water providers. Kalsoum Abbasi, a water engineer with Colorado Springs Utilities said that, if there’s too much runoff, they can’t collect all they are entitled to divert, and it continues down the river. Early melting can also have an effect on river ecology. Abby Burk is the Western Rivers Program Lead for Audubon Rockies. She said intense and early runoffs can affect aquatic insects, riparian trees and shrubs—and even change river channels.
So what will be the effect of this recent dust event? To figure that out Jeff Derry and his colleagues look for dust in Colorado’s snowpack by digging snow pits—a method for which he says there is really no substitute. By doing that they see the layers of dust and can analyze its effect on runoff. They go all around the Colorado mountains, north to south and east to west digging snow pits to measure the dust layers. Spring months are the biggest ones for dust events, so Derry’s team will go dig pits in March, April and May. They’ll share what they find with water managers and river forecast centers.
But, as far as this recent dust event goes, they won’t know the impact until they’ve dug all those snow pits.