Crested Butte Avalanche Center

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Reported Monday, February 8, 2010 at 5:40 AM

	Weather Forecast Today: Partly cloudy, trace to 1 inch of snow possible in the morning, west winds 5-10 mph and highs in the upper 20s in Crested Butte and low 20s in Gunnison. Tonight: Mostly clear, light northwest winds and lows around 5 in Crested Butte and -5 in Gunnison. Tomorrow: Partly sunny, west winds 5-10 mph and highs in the mid 20s in Crested Butte and upper teens in Gunnison.

This weekend’s storm dropped just under 6 inches of snow in town and 8-10 inches in the high-country. Temperatures will remain mild with calm winds as the low-pressure system tracks south and east of Colorado today. After a brief clearing today and tomorrow, more pacific moisture will move into the southwest keeping the weather in the Elk Mountains unsettled throughout the week.

Both town and CBMR are reporting 5-6 inches of snow and 0.3 inches of water in the last 48 hours; Schofield Pass is reporting 0.6 inches of water from this weekend. The storm snow arrived with warmer temperatures and light winds. Observers have reported sluffing on steep shadier slopes below tree-line. Light winds have created shallow and soft wind slabs on lee and cross-loaded slopes near and above tree-line. We received a report of a skier triggered avalanche yesterday afternoon from the Pencil on Mt. Axtell. The slide was triggered remotely from the ridge and ran on the new snow/old snow interface with a reported 18 inch crown. Storm snow fell on weak surface crystals on shady aspects. In areas where the wind has re-distributed and stiffened the snow or where denser storm snow is resting over weak layers, slab avalanches have the potential to be fast moving and propagate farther than expected.

Our other concern remains several buried weak layers that continue to plague our snowpack. These persistent weak layers are present on all aspects and elevations. On sunny aspects, buried facets sandwiched between two melt-freeze crusts continue to pose a threat especially on steeper slopes. Buried surface hoar and buried surface facets as well as weak basal facets and depth hoar are still lingering on shady aspects. Storm snow from two weeks ago has formed a cohesive slab that is supportive in many areas. However, the weight of a skier has a good possibility of penetrating through the slab and affecting buried weak layers in areas near and around trigger points. Common trigger points include trees, rocks, convex rolls and all areas of shallow and weak snow.

The danger is CONSIDERABLE near and above tree-line on north through south-east aspects. The danger is MODERATE at all other aspects and elevations.

LIKELIHOOD OF TRIGGERING

AVALANCHE SIZE

Trend

Soft shallow slabs have formed from this weekend's storm snow near and above tree-line. They are resting on weak surface crystals and may be reactive to light loads. While natural avalanches are not likely today, a report of a remote triggered soft slab avalanche on Mt. Axtell indicates instability in the upper snowpack. Human triggered avalanches remain probable on steep wind-loaded aspects near and above tree-line.

LIKELIHOOD OF TRIGGERING

AVALANCHE SIZE

Trend

Buried weak layers exist on all aspects and elevations and will be most commonly affected from areas of shallow or weak snow.

Use caution if you elect to ski in steeper terrain today. More snow fell at higher elevations, and if you are traveling near and above tree-line be sure to inspect the depth and stiffness of the storm snow as well as what it is resting on. Don’t get lulled into complacency by a fresh blanket of snow; a complex and variable snowpack still exists out there.

MacKinnon