Mon, May 10, 2021 at 3:58pmIssued by: Jason Konigsberg
You can trigger avalanches where winds have drifted snow near ridgetop. With up to 6 inches of snow, wind drifts can be over a foot thick. A small avalanche can take you off your feet resulting in injury in high-consequence terrain. Watch for shooting cracks in the new snow and evaluate how the new snow is bonding before committing to any steep slope.
A trough of low pressure over the Great Basin is driving weather across Colorado on Monday. Banded precipitation transitions to convective snow showers Monday afternoon. Although the Front Range is favored, some snowfall spills further west to the Mosquito and eastern Sawatch Ranges, with three to six inches possible by Tuesday morning. High temperatures will be in the thirties. Snowfall ends with gradual clearing Tuesday night and lows in the twenties. Temperatures gradually warm through the rest of the week as a breezy northwesterly flow becomes more westerly.
Snowpack and Avalanche Discussion
As of 4 PM Monday, ski areas around Aspen picked up close to six inches of snow. Favored areas for snow shift east tonight. By late Tuesday most of the Central Mountains will be in the three to six inch range. With moderate westerly winds, slabs will form on easterly-facing slopes, especially above treeline. Avalanches that you can trigger in wind-drifted snow will be small but you will have to evaluate these drifts for yourself if you plan to get into extreme terrain. It is hard to say if these slabs will be reactive. Spring storms with warm temperatures generally result in a good bond to underlying crusts and old snow layers. You'll have to dig down and evaluate for yourself though and be wary of the bond between old and new snow if you see shooting cracks.
Another thing to look for is a dust layer under the new snow. This old dust layer probably saw a bit of faceting while it was buried and in some places this dust/facet layer was on the surface prior to the new snow.
With the past few spring storms, the more dangerous time has come with the reappearance of the sun. It doesn't take much of the strong May sun to heat up the snow and start seeing natural avalanches. We think that this will happen on Wednesday but if you are out on Tuesday, and the clouds begin to break, be on guard for moist snow sliding on underlying crusts, resulting in wet avalanches.