Avalanche Canada dsaly, Avalanche Canada

South Rockies Avalanche Forecast

Mar 28th, 2020 5:00PM

The alpine rating is moderate, the treeline rating is moderate, and the below treeline rating is low. Known problems include Wind Slabs, Loose Wet and Deep Persistent Slabs.

This forecast lacks field observations and has lots of uncertainty. This will be the last avalanche forecast of the season. Reactive wind slabs remain the primary concern, especially around ridge features and wind loaded terrain.

Summary

Confidence

Low - Uncertainty is due to the limited number of field observations.

Weather Forecast

Saturday night: Cloudy with isolated flurries, trace to 5 cm. Alpine low temperature -6 C. Moderate to strong southwest wind. Freezing level to valley bottom.

Sunday: Cloudy with scattered flurries, trace to 10 cm. Alpine high temperature -1 C. Moderate gusting to strong southwest wind. Freezing level 1900 m.

Monday: Flurries, 5-15 cm. Alpine high temperature -6 C. Moderate gusty southwest wind. Freezing level 1700 m and dropping.

Tuesday: Cloudy with scattered flurries, 5-10 cm. Alpine high temperature -10 C. Light east wind. Freezing level valley bottom.

Avalanche Summary

We have very limited field observations at this time. There have be no new avalanches reported in the region.

Snowpack Summary

Recent snow has been impacted by wind and warm temperatures. Cold, dry snow persists at higher elevations and consists of a variety of wind affected surfaces and a crust on sun-exposed slopes. A crust is on steep solar slopes and below tree line. 

A layer of faceted grains down 40-80 cm overly a melt-freeze crust from early February. The base of the snowpack contains basal facets that are most prominent in shallow, rocky start zones.

Terrain and Travel

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Avoid shallow, rocky areas where the snowpack transitions from thick to thin.

Problems

Wind Slabs

An icon showing Wind Slabs

Likelihood

Possible-Likely

Expected Size

1 - 2

Steady winds continue to impact loose, dry snow. The most reactive deposits will be on leeward slopes, particularly near ridgetop.

Aspects:

North, North East, East, South East, North West.

Elevations:

Alpine, Treeline.

Loose Wet

An icon showing Loose Wet

Likelihood

Unlikely-Possible

Expected Size

1 - 2

Rising freezing levels and precipitation may trigger snow shedding from steep slopes.

Aspects:

All aspects.

Elevations:

Alpine, Treeline.

Deep Persistent Slabs

An icon showing Deep Persistent Slabs

Likelihood

Unlikely-Possible

Expected Size

2.5 - 3.5

Weak snow at the bottom of the snowpack hasn't gone away. Evidence of deep persistent slab avalanches has been focused in the Sparwood-Elkford area over the past month. Human triggering is most likely around steep, rocky terrain features or anywhere the snowpack is thin and weak. A failing cornice could initiate a deep persistent slab when it impacts the slope below.

Aspects:

All aspects.

Elevations:

Alpine, Treeline.

Valid until: Mar 30th, 2020 5:00PM