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North Rockies Avalanche Forecast - March 16, 2021

Spring-like conditions will persist through the forecast period. Natural avalanche activity will likely spike in the afternoon when warming and solar radiation destabilizes the snowpack.
North Rockies Avalanche

Spring-like conditions will persist through the forecast period. Natural avalanche activity will likely spike in the afternoon when warming and solar radiation destabilizes the snowpack.

Tuesday

Alpine - Moderate
Treeline - Moderate
Below treeline - Low

Wednesday

Alpine - Moderate
Treeline - Low
Below treeline - Low

Thursday

Alpine - Moderate
Treeline - Low
Below treeline - Low

Avalanche Summary

The warm weekend proved to show a widespread natural avalanche cycle primarily loose wet up to size 2 but natural cornice failures were reported as well as some wet slabs seen up to size 2 and potentially larger. Check out these excellent MIN reports from Saturday.

With warming and solar input continued, it might lead to deeper releases on the persistent weak layer this week.

Our field team found some large and disturbingly wide avalanches in the Hasler last Tuesday, with lots of compelling images in their MIN report here. It's suspected that these are running on facets that are about 80 cm below the surface.

This adds to the tally of recent large avalanches they started collecting in Pine Pass on Monday.

Snowpack Summary

The northern portion of the region around the Pine Pass has picked up 35 new cm as of Saturday afternoon but very little new precipitation has fallen in the southern 2/3 of the region. This snow is expected to be redistributed by the strong southwest wind and also felt the heat of the rising freezing levels over the weekend.

Sun crust exists on solar aspects and a temperature crust may exist on all aspects to 1800 m. Wind effect is widespread in the alpine and treeline across the region.

About a metre of snow covers a weak layer of facets buried mid-February. Slightly deeper there is a widespread persistent weak layer from late January/early February that consists of surface hoar. It is most prevalent around treeline elevations, but likely reaches into the alpine and in openings below treeline too. These layers are both significantly shallower in the east of the region.

Weather Forecast

A spring-like diurnal weather pattern is expected through the forecast period. This will bring rising freezing levels to 2000 m by the afternoon then falling back to the valley bottom overnight. No new snow is expected and mostly sunny skies will prevail.

Travel and Terrain Advice

  • Avoid avalanche terrain during periods of strong sun.
  • A moist or wet snow surface, pinwheeling and natural avalanches are all indicators of a weakening snowpack.
  • Minimize overhead exposure; avalanches triggered by warming or cornice fall may be large and destructive.
  • Be aware of the potential for large avalanches due to the presence of a deep persistent slab.