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. 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
Highest snowfall amounts will be on southwestern facing slopes in the Monashees and northern Selkirks. Below the freezing level, precipitation will fall as rain.
Saturday night: 10-20 cm new snow. Moderate to strong southwest winds. Alpine temperatures around -5. Freezing level 1500 m.
Sunday: Continued flurries bringing up to 5 cm. Light northwest wind. Alpine high temperatures around -6. Freezing level 1500 m.
Monday: Sunny. Light to moderate west 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 2200 m.
Avalanche Summary
No reports of avalanche activity since Wednesday when small (size 1) natural and skier triggered loose wet avalanches were observed on south aspects, running on a recent crust layer. One recent natural size 2 cornice failure was also noted.
On Tuesday, a skier triggered size 2.5 involvement was reported in neighboring Glacier National Park resulted in lost gear and minor injuries. The avalanche is suspected to have run on a buried crust in the upper snowpack.
Snowpack Summary
5-20 cm of new snow arrives overnight with moderate to strong southwest wind. This has likely added to wind affected surfaces and cornices in the alpine and to settled dry snow on sheltered, shaded aspects above about 1900 m. Below this elevation and on solar aspects the new snow dusts crusty surfaces down to 1500 m. Below this elevation, the moist snowpack is quickly diminishing.
At alpine and treeline elevations, a widespread crust exists (except on north-facing slopes above 1800 m) buried 50-100 cm deep. Overall the snow seems to be bonding well at this interface, although there have been a few isolated avalanches running on deeper crust layers over the past few weeks.
Terrain and Travel
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Closely monitor how the new snow is bonding to the crust.
- 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 arriving overnight with moderate wind may result in some fresh wind slabs by Sunday morning. They will be most likely be isolated to immediate lees of ridgecrests and roll-overs in wind exposed alpine terrain. Storm snow may be most reactive where it sits over a crust.
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, North West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Apr 4th, 2021 4:00PM
