SNOWPACK VERY POORLY STABILIZED: NUMEROUS SLABS STILL VERY REACTIVE.

WITH THE DAYTIME WARMING, NUMEROUS NATURAL RELEASES IN THE MID-MOUNTAINS.

Risk level: 4 - High

Description:
SNOWPACK VERY POORLY STABILIZED: NUMEROUS SLABS STILL VERY REACTIVE.
WITH THE DAYTIME WARMING, NUMEROUS NATURAL RELEASES IN THE MID-MOUNTAINS.

Issuance of a Special Avalanche Bulletin (CSA).

Triggered releases: numerous slabs still very sensitive to the passage of a skier. The northwest wind has contributed to forming these slabs, which are soft at the foot and base of slopes with sometimes few visual clues, and sometimes already hard when approaching ridges where the wind has been locally very strong. Given the heavy accumulations of recent snow, the crown fractures can be very thick, generally resulting in size 2 (medium) avalanches. These slabs are found on all aspects, mostly above 2000/2200 m.
An aggravating factor: above 2000 m and on cold aspects (East/North/West), and even on South aspects at high altitude, persistent weak layers buried in the snowpack may still react to the passage of a skier or in a cascade following an initial slab: they then generate larger and wider avalanches (size 3).

Spontaneous releases: with the return of the sun and the relative warming (0°C isotherm around 2000 m in the afternoon), we expect:
(1) On all aspects below 1800/2300 m, numerous glide slabs and bank slides, especially on steep, grassy slopes. Since snow depths are significant even at these mid-altitudes (100-150 cm), the volumes involved are substantial, and the resulting size 1 to 2 avalanches could affect high-altitude roads or parking lots.
(2) On South aspects up to high altitude, a few point releases in the moistening fresh snow. Generally sizes 1 (small) to 2, but an exceptional size 3 avalanche triggering the buried persistent weak layer in a cascade is not excluded.

SNOWPACK VERY POORLY STABILIZED (the layers of snow haven't bonded together yet): NUMEROUS SLABS (compacted layers of snow sitting on a weaker base) STILL VERY REACTIVE (easy to trigger).

WITH THE DAYTIME WARMING (temperatures rising above freezing), NUMEROUS NATURAL RELEASES (avalanches starting on their own without human contact) IN THE MID-MOUNTAINS.

Risk Level 4 - High: This means very dangerous conditions. Natural avalanches are likely, and human-triggered avalanches are very likely. Travel in avalanche terrain is not recommended.

Special Avalanche Bulletin (CSA): This is an official warning issued by weather services when avalanche conditions are particularly critical.

Triggered releases (avalanches caused by people): Many slabs are very sensitive to the weight of a single skier. Northwest winds have created these slabs. They can be 'soft' (friable) at the bottom of slopes, which is dangerous because they often have 'few visual clues'—meaning the snow looks normal or fluffy even though it is ready to slide. Near ridges, the snow might be 'hard' or wind-crusted because the wind was stronger there. Because so much snow has fallen (heavy accumulations), the 'crown' (the top edge where the slab breaks away) can be very deep, leading to Size 2 avalanches (large enough to bury or kill a person). These are found on all 'aspects' (the direction a slope faces, like North or South).

Persistent Weak Layers: These are 'hidden traps'—thin, fragile layers of snow (like a house of cards) buried deep underground. On cold slopes (North, East, West) or very high South slopes, these layers can collapse when a skier passes over them. This can also cause a 'cascade' (step-down) effect where a small slide triggers a much bigger one, resulting in Size 3 avalanches (large enough to destroy a car or small building).

Spontaneous releases (Natural avalanches): As the sun comes out and the '0°C isotherm' (the altitude where the temperature is exactly freezing) rises to 2000m, the snow will melt and get heavy. We expect:

1. Glide slabs (plaques de fond): The entire snowpack sliding off the ground like a rug on a hardwood floor, especially on steep grass. Because there is 100-150cm of snow, these can be massive and hit roads or parking lots.
2. Point releases: Small 'sluffs' of wet snow that start from a single point. These are usually Size 1 (small) to Size 2, but could trigger the deeper weak layers mentioned above.