Avalanche Forecast
Issued: Apr 3rd, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs and Cornices.
ahanna,
Avalanche Canada
Winter is still hanging on up there, with a fresh hit of snow arriving overnight and into Sunday. The new snow may be reactive in wind loaded features or where it sits over a crust. Check out our latest forecaster blog on managing these not-quite-yet-spring conditions.
Summary
Confidence
Moderate - Forecast precipitation (either snow or rain) amounts are uncertain.
Weather Forecast
Light precipitation spreading from north to south overnight Saturday into Sunday. Local enhancements of up to 20 cm may be found on southwest facing slopes in high elevation areas. Below the freezing level, precipitation will fall as light rain.
Saturday night: 5-10 cm new snow focused in the north of the region. Strong southwest wind. Alpine temperatures around -3. Freezing levels to 1500 m.
Sunday: 5-10 cm new snow focused in the south of the region. Light northwest wind. Alpine high temperatures around -6. Freezing level 1600 m.
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. Light to moderate south wind. Alpine high temperatures around -1. Freezing level 2300 m.
Avalanche Summary
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.Â
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
Surface crusts exist on solar aspects and below about 2000 metres. Above this elevation, 20-50 cm of recent snow in the Selkirk mountains and 10-20 in the Monashees has otherwise seen some redistribution by southwest to northwest wind, and seems to be bonding well with underlying surfaces.
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
- Closely monitor how the new snow is bonding to the crust.
- Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
- Extra caution is needed around cornices under the current conditions.
- A moist or wet snow surface, pinwheeling and natural avalanches are all indicators of a weakening snowpack.
Problems
Storm Slabs
New snow may be most reactive where it is wind affected or sits over a crust. In areas where the bulk of snow arrived overnight may see some wind effect most likely 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 4th, 2021 4:00PM
