Avalanche Forecast

We’re entering a rather quiet period with no significant snow expected for the foreseeable future, aside from some meager flurries mid week. The next 48 hours are marked by cool temps, rather well behaved winds and potentially sunny periods.

SATURDAY NIGHT: Freezing level at valley bottom, light northwest wind largely confined to the high peaks, no significant precipitation expected.

SUNDAY: A few clouds, freezing level at valley bottom, moderate northwest wind at ridgetop, no significant precipitation expected.

MONDAY: Scattered cloud cover, freezing level at valley bottom, moderate west/northwest wind, light snow beginning after dark, potential for 1 to 3 cm by Tuesday morning.

TUESDAY: Scattered cloud cover, freezing level around 700 m, moderate to strong southwest wind, trace of snow expected during the day.

The south of the region has been reporting skier triggered loose dry avalanches in old, faceted snow up to size 1.5. A common theme surrounding recent avalanche activity is that avalanches are most often triggered in shallow snow in steep, rocky terrain, then propagating out into thicker snowpack areas, sometimes stepping down to deeper persistent weak layers.There have been numerous reports from the north half of the region of natural wind slab and persistent slab avalanches averaging size 2, which follow this trend.

So far this season's snowpack is shaping up to be quite complex with a high degree of variability even over short distances. Snow depth is highly variable with many thin, rocky areas where the snowpack is primarily composed of sugary facets and depth hoar. These are common trigger points for avalanches, which then propagate out into thicker snowpack areas.

Here's a general synopsis of the snowpack top to bottom:

The key element of the upper snowpack is wind slab in the alpine, especially in lee features such as ridge tops and gullies.

The mid snowpack is characterized by layers of surface hoar crystals often in combination with crusts or other firm surfaces, which make for pretty classic sliding surfaces for overlying slabs.

The lower snowpack is composed of decomposing crusts, facets, and depth hoar. These very weak crystals supporting the weight of the snowpack are a major concern and are the basis for the deep persistent slab problem. Avalanches associated with this problem would be large, involving the full depth of the snowpack.