The Valentine’s Day storm from the south that blew Arizona’s desert dust onto Colorado’s mountains did more than paint the state’s snowpack a pinkish hue.
It created a laboratory for the state’s eager snow scientists.
No one is quite sure what happens to snow stability after a thick dusting. But rest assured, after the recent snowfall – the first real snow since the mid-February storm – scientists will be watching closely.
“This really will be a fascinating year to explore and study this,” said Tom Painter, a researcher with the National Snow and Ice Data Center.
There is little scientific data exploring the impact of a dust layer on snowpack. There are plenty of theories, though.
The darker hue tends to absorb twice as much sunlight as pure snow, contributing to potential instability below the dust layer. Add a fresh layer of snow on top of the well-baked dust layer, and the new snow could heat up and become a potential avalanche layer when it freezes at night.
New snow already has been sliding off the frozen dust layer on north-facing aspects atop Loveland Pass, according to reports posted by the Colorado Avalanche Information Center.
The renewed exposure of the dust layer to sunlight after a slide could increase the likelihood for more instability beneath the dust layer, said Nick Logan, a CAIC avalanche forecaster in Summit County.
But in other areas the dust layer has absorbed so much sunlight that the snow has “cupped,” creating a rough-hewn layer that bonds more easily with new snow.
The dust event is not new for southern Colorado, where southern winds blow Arizona and Utah desert dirt into the San Juan Range as often as four times a year. It is rare for the dust to coat the entire state’s mountains, as it did last month.
“It was a memorable event. We are watching it and monitoring it closely,” Logan said. “We don’t have a lot of scientific evidence on how dust layers affect snow and avalanches.”
