Avalanche Forecast
Issued: Apr 4th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Cornices.
ahanna,
Avalanche Canada
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.
Summary
Confidence
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 slabs will be most likely be isolated to immediate lees of ridgecrests and roll-overs in wind exposed alpine terrain.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Cornices
Cornices become weak with daytime warming. Cornice falls are dangerous in their own right and they can also trigger slabs on slopes below.
Aspects: North, North East, East, South East.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Apr 5th, 2021 4:00PM
