Change is here! The dry weather finally comes to an end this evening. A storm enters Colorado with the West Elk and Elk mountains forecast to receive the most snow in the Central Mountains. These mountain ranges could see 5 to 7 inches of snow while most other areas will see 2 to 4 inches of snow.
After the extended dry period, our snowpack has grown very weak. Since our last storm on November 24th, we have had unseasonably warm and sunny days followed by cold and clear nights. During this period, most slopes that still held snow faceted to the ground. Some wind-loaded terrain features still hold a slab of firm snow that rests on facets. Southerly slopes with continuous snow coverage have developed surface crusts from warm sunny days, and observers have reported widespread surface hoar to exist on shadier aspects. This is a dangerous combination of weak layers that are about to be buried by a series of storms this week.
After tonight's storm, expect to see avalanches in areas where 6 or more inches of snow accumulate on top of a very weak snow surface. Even 3 or 4 inches of snow with some moderate winds could produce small avalanches on leeward slopes. North, northeast, and east facing slopes will see the most avalanches as the storm snow settles, but any slopes that harbor continuous snow coverage and receive the high end of predicted snowfall will be a concern.
Wednesday looks to be a day of dry weather before the second storm arrives later this week. This storm is still too far out to have reliable snowfall totals, but it looks to be the most significant winter storm so far this season.
The bottom line is avalanche danger is going to rise rapidly throughout the week. The current state of the snowpack has set us up for dangerous conditions as snow begins to accumulate. Check back frequently for the most up to date avalanche information as we continue to track the incoming storms.