Avalanche Forecast
Issued: Mar 18th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs and Cornices.
swerner,
Avalanche Canada
New snow and strong wind may form isolated pockets of fresh wind slab.
The region will see mostly cloud cover on Friday, but if the sun shines it could heat up fast. Pay attention to steep South facing slopes and back off if they heat up
Avoid exposure above or below cornices
Summary
Confidence
Moderate - Forecast snowfall amounts are uncertain.
Weather Forecast
A Pacific frontal system reaching the Coast today will bring cloudy skies and snowfall to the Interior regions through the weekend.
Thursday Night: Snow 5-10 cm. Ridgetop wind moderate from the southwest and alpine temperatures near -5. Freezing levels 1300 m.
Friday: Cloudy with sunny periods and possibly 5-10 cm. Ridgetop wind strong from the southwest and freezing levels 1500 m.
Saturday: Mix of sun and cloud. Ridgetop wind strong from the West and alpine temperatures near -8. Freezing levels 1300 m.
Sunday: Snow 5-10 cm. Ridgetop wind light to moderate from the southwest. Freezing levels 1200 m.Â
Avalanche Summary
No new avalanche reports on Wednesday, however, there were a few reports of lower elevation (below treeline) that showed evidence of wet slab and loose wet avalanches up to size 2. They proved to be a few days old.Â
On Tuesday, a size 3.5 deep slab avalanche was reported from the Northern Monashees. It was triggered by cornice fall on an east-southeast aspect above 2200 m. Additionally, a natural glide slab size 2.5 was reported from a West aspect at 1500 m and numerous loose wet to size 2 in steep southerly terrain.Â
On Monday, numerous natural loose wet avalanches were reported from southerly aspects above 1900 m.
Snowpack Summary
Isolated wind slabs may form just below ridgelines with new snow and strong wind. Snow surfaces vary at the moment. Surface hoar up to 10 mm in size exists at treeline and above. Sunny skies and warm temperatures formed sun crusts on solar aspects and at all elevations and up to 2000 m on polar aspects. Dry snow still exists on north aspects at upper elevations. Large cornices loom over alpine ridgetops.
Persistent weak layers of surface hoar, crusts, and/or facets 80-120 cm down have recently been unreactive and no recent avalanches have been reported on these layers.Â
Terrain and Travel
- Watch for wind-loaded pockets especially around ridgecrest and in extreme terrain.
- Use caution above cliffs and terrain traps where even small avalanches may have severe consequences.
- Cornices become weak with daytime heating or solar exposure.
- Rocks will heat up with daytime warming and may become trigger points for loose wet avalanches
Problems
Wind Slabs
Increasing winds on Friday accompanied by 5-10 cm of new snow may form wind slabs in isolated alpine locations. Steep, convex slopes below alpine ridgetops are the most likely places to trigger these slabs.
If the sun pokes out it may have enough punch to initiate the recent snow as loose wet or dry avalanches from steep terrain features.
Aspects: North, North East, East.
Elevations: Alpine.
Likelihood
Expected Size
Cornices
Periods of sunshine breaking through the clouds could pack enough punch to increase the likelihood of cornice failures. Recently a cornice fall triggered a very- large slab avalanche from the slope below. These events are fairly unpredictable so the best way to mitigate the risk is to minimize your exposure, especially when solar radiation is strong.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Mar 19th, 2021 4:00PM
