Avalanche Forecast
Issued: Apr 2nd, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Wind Slabs, Cornices and Loose Wet.
ahanna,
Avalanche Canada
High elevation north aspects hold the best snow but are also the most likely place to encounter wind slabs. Be ready to back off slopes as warm temperatures moisten and weaken the upper snowpack. Check out our latest blog post on managing these not-quite-yet-spring conditions.
Summary
Confidence
High -
Weather Forecast
Friday night: Partly cloudy. Light to moderate southwest winds. Alpine high temperatures around -2. Freezing levels dropping to 800 m in the north and holding at 2000 m in the south.
Saturday: A mix of sun and cloud. Light to moderate southwest winds. Alpine high temperatures around 0. Freezing levels to 2200 m.
Sunday: 5-15 cm new snow arriving overnight around Golden and during the day farther south. Light southwest wind shifting northwest over the day. Alpine high temperatures around -5. Freezing level 1700 m.
Monday: Sunny. Light to moderate west wind. Alpine high temperatures around -2. Freezing level 2000 m.
Avalanche Summary
A natural size 3 was reported on Thursday in the Dogtooth range. It was on a southeast aspect in the alpine and is suspected to have solar-triggered and run on the crust buried in mid-March. Cornices were noted to be reactive but were not observed to trigger slabs on slopes below.
Reports from Wednesday showed a trend of small (size 1) wet loose point releases from steep solar aspects. Explosives control in the Golden area produced several small (size 1) wind slab releases from north through east facing ridgetop features. Minimal propagation was noted in these results.
On Monday, numerous skier and explosive triggered storm slab avalanches were reported size 1-1.5, largely on NW aspects. By Tuesday, storm slabs became more stubborn to explosives and results were limited. Observations in the Hellroaring area, which received less snow, include a few size 1 wind slabs and a cornice-triggered size 1.5.
Snowpack Summary
Surface melt-freeze crusts exist on solar aspects and below about 2000 metres. Above this elevation, 15-40 cm of recent snow has otherwise seen some redistribution by southwest to northwest wind, and seems to be bonding well with underlying surfaces.
A widespread crust layer from the mid-March warm spell can be found 30-60 cm deep, and small surface hoar has been observed at this depth on some isolated north-facing slopes. Reports suggest the snow is generally well bonded to these layers but isolated instances of large solar-triggered slab avalanches running on the crust have been observed. Deeper layers are strong and have been unreactive over the past few weeks.
Terrain and Travel
- Small avalanches can have serious consequences in extreme terrain. Carefully evaluate your line for wind slab hazard before you commit to it.
- Extra caution is needed around cornices under the current conditions.
- Avoid steep slopes when air temperatures are warm, or solar radiation is strong.
- A moist or wet snow surface, pinwheeling and natural avalanches are all indicators of a weakening snowpack.
Problems
Wind Slabs
Recently formed wind slabs may remain reactive to human triggering in wind loaded terrain features at upper elevations.
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. Their large mass can trigger deeper slabs on buried crusts in the upper snowpack that a single rider wouldn't trigger on their own.
Aspects: North, North East, East.
Elevations: Alpine.
Likelihood
Expected Size
Loose Wet
Wet loose avalanches are possible on steep south facing slopes and at elevations where air temperatures rise above freezing.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Apr 3rd, 2021 4:00PM
