Dashboard Regions Weather Stations Radar Alerts Glossary
Contact About
Log In

Register for an account and never miss a forecast again!

Register

Avalanche Forecast

Archived

Apr 4th, 2021–Apr 5th, 2021

Alpine
Natural avalanches unlikely, human triggered possible.
Treeline
Natural avalanches unlikely.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches unlikely.
Treeline
Natural avalanches unlikely.
Below Treeline
Natural avalanches unlikely.
Alpine
Natural avalanches unlikely.
Treeline
Natural avalanches unlikely.
Below Treeline
Natural avalanches unlikely.

Regions

South Columbia.

Minimize exposure to large looming cornices weakening in the sun on Monday. The new snow will be prone to point releases on south facing slopes and wind slabs may be found in immediate lees of exposed alpine terrain features.

Confidence

High -

Weather Forecast

Sunday night: Partly cloudy. Light to moderate northwest wind. Alpine temperature -7. Freezing level valley bottom.

Monday: Sunny. Light to moderate northwest wind. Alpine high temperatures around -2. Freezing level 2000 m.

Tuesday: Sunny with increasing cloud in the late afternoon. Wind increasing to moderate to strong southwest. Alpine high temperatures around -1. Freezing level 2100 m.

Wednesday: 5-10 cm new snow. Strong southwest wind easing to light. Alpine temperature around -8. Freezing level 1500 m.

Avalanche Summary

A size 2 skier triggered wind slab was reported in neighboring Glacier National Park on Saturday. A couple of size 2 cornice failures were reported on Friday, one triggering a thin wind slab on the slope below. On Wednesday and Thursday, natural and skier triggered loose wet avalanches were reported on solar aspects size 1-2.5. 

Sporadic slab avalanches around size 2 have also been observed running on one or more of our recent curst layers. On Wednesday a larger (size 2), 45 cm-deep slab was triggered by a snowcat push in the Selkirks and is suspected to have failed on a surface hoar layer from late March.

Snowpack Summary

5-15 cm of recent snow may have seen some wind effect in immediate less of exposed alpine features. Reports indicate it is bonding well to underlying surfaces which include wind affected snow in the alpine or crust on solar aspects and below 1900 m. Below this elevation and on solar aspects the new snow dusts crusty surfaces down to 1500 m. Below 1500 m, the moist snowpack is quickly diminishing.

At alpine and treeline elevations, a few layers of note are buried 50-100 cm deep including a layer of small surface hoar crystals on shady, wind-sheltered aspects and a series of crusts on solar aspects and below 1800 m. Overall the snow seems to be bonding well to these interfaces, although there have been a few isolated avalanches running on deeper crust layers in the past week.

Terrain and Travel

  • Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.
  • Rocks will heat up with daytime warming and may become trigger points for loose wet avalanches
  • Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.

Problems

Wind Slabs

Wind Slab avalanches are the release of a cohesive layer of snow (a slab) formed by the wind. Wind typically transports snow from the upwind sides of terrain features and deposits snow on the downwind side. Wind slabs are often smooth and rounded and sometimes sound hollow, and can range from soft to hard. Wind slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.

Cornices

Cornice Fall is the release of an overhanging mass of snow that forms as the wind moves snow over a sharp terrain feature, such as a ridge, and deposits snow on the downwind (leeward) side. Cornices range in size from small wind drifts of soft snow to large overhangs of hard snow that are 30 feet (10 meters) or taller. They can break off the terrain suddenly and pull back onto the ridge top and catch people by surprise even on the flat ground above the slope. Even small cornices can have enough mass to be destructive and deadly. Cornice Fall can entrain loose surface snow or trigger slab avalanches.