Weekly Climate, Water and Drought Assessment of the Upper #ColoradoRiver Basin


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Snowpack news: Aspen snowpack dust-free for first March in a decade — The Aspen Times

Westwide SNOTEL snow water equivalent as a percent of normal March 25, 2015 via the NRCS
Westwide SNOTEL snow water equivalent as a percent of normal March 25, 2015 via the NRCS

From The Aspen Times (Scott Condon):

The Center for Snow and Avalanche Studies, a nonprofit organization based in Silverton, said no dust has been observed at 11 high-elevation sites that it monitors around the state, including McClure Pass on state Highway 133. The organization has operated the Dust-On-Snow Program since 2005.

Last winter, there were three major dust storms at the Senator Beck Basin, a sentry site for the organization in the San Juan Mountains. The dust affected many other sites, as well. Skiers at the Aspen-Snowmass ski areas negotiated a red layer of grit on the snow.

The dust does more than mess up the slopes. It reduces the reflective ability of the snowpack, said Chris Landry, a former Roaring Fork Valley resident who is executive director of the Center for Snow and Avalanches. Clean snow reflects solar energy from the sun pretty effectively, he said. Dust is “the 800-pound gorilla” because it absorbs the sun’s energy and the snowpack melts more quickly.

“That’s why dust is so important — it completely alters the absorption,” Landry said.

The snowpack isn’t in the clear yet. History shows that dust gets deposited in April and May, as well. Spring storms on the Colorado Plateau blow in dust from the south and west of Aspen. When accompanied by rain or snow, it sometimes creates a scenario where it rains mud.

The snowpack — the lifeblood for much of the arid West — needs any break it can get this year. The overall snowpack level for the Upper Colorado Basin, which covers much of the Central Mountains, is 89 percent of average for this time of year, according to the U.S. Natural Resources Conservation Service.

Not only is the snowpack below average, but it is already substantially eroded on sunny slopes on east, west and south aspects, Landry and his colleagues discovered on a tour of the center’s 11 sites March 17 through Friday. Lower elevations are already melted out in many areas, according to an update on the center’s website.

In addition, the center found that the snowpack has ready warmed to 0 degrees Celsius in many places. That means any energy consumed by the snowpack will result in melting rather than cooling the layers down.

“People refer to this as a ripe snowpack,” Landry said. “Just add energy and you’ll get water.”

How the warming climate is transforming your garden: Planting zones are marching northward — @AssaadRazzouk