Avalanche Forecast
Regions: South Coast Inland.
There is substantial uncertainty regarding storm snow totals by Monday afternoon but it is likely enough to create dangerous avalanche conditions. The storm snow is expected to be touchy throughout the region and the deeper snowfall areas may see a natural avalanche cycle.
Confidence
Low - Uncertainty is due to the timing, track, & intensity of the incoming weather system.
Weather Forecast
A storm system is expected to continue to impact the region until Tuesday morning. Heavy snowfall is expected for the immediate coastal regions but there is substantial model variability regarding how much will make it to the inland region.
Sunday Night: Snowfall 10-30 cm, strong SW wind, freezing level low around 1000 m/high around 1500 m.Â
Monday: Snowfall 10-30 cm, strong SW wind, freezing level high around 1300 m.Â
Tuesday: Mainly cloudy with lingering flurries, moderate W wind, freezing level high around 1400 m.
Wednesday: Mainly sunny, light variable wind, freezing level high around 1800 m.
Avalanche Summary
On Saturday in the north of the region, a skier triggered a size 1 wind slab on a northeast aspect at 2450 m which had an average thickness of 25 cm and slid on a melt-freeze crust. In the Coquihalla area, this MIN report and this MIN report describe small skier-triggered soft slab avalanches which were 5-20 cm thick. This MIN report describes wind loading and shooting cracks in the recent 10-15 cm of storm snow.Â
On Friday, a ski cut in the north of the region triggered a size 1 wind slab on a northeast aspect at around 2200 m elevation which was 15-20 cm thick. In the Coquihalla area, two natural cornice releases were reported on northwest aspects and a size 1 solar-triggered loose dry avalanche was observed in the alpine.Â
Snowpack Summary
The new storm snow will continue to bury a strong, supportive crust which extends to mountain top on solar aspects and to around 2200 m on northerly aspects. Strong southwest wind will be redistributing the new storm snow in exposed high elevation terrain forming touchy wind slabs and building large cornices.Â
The rest of the upper snowpack consists of a number of crust/facet/surface hoar interfaces buried in March that seem to have bonded well during the recent warm weather.Â
The middle and lower snowpack are generally strong and well bonded.Â
Terrain and Travel
- Watch for fresh storm slabs building throughout the day.
- Make conservative terrain choices and avoid overhead hazard.
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- Extra caution is needed around cornices under the current conditions.
Avalanche Problems
Storm Slabs
New snowfall with moderate to strong southwest wind is expected to form touchy new storm slabs on Monday, especially in wind loaded terrain. These slabs will likely be failing on a firm crust underlying the recent storm snow.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Likely - Very Likely
Expected Size: 1 - 2.5
Cornices
Large cornices will continue to grow during the storm and have the potential to fail naturally.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood: Possible - Likely
Expected Size: 1 - 2
Loose Wet
Rain at lower elevations may destabilize the upper snowpack. Loose wet avalanches are most likely at elevations where rain soaks recent snowfall overlying a hard melt-freeze crust.
Aspects: All aspects.
Elevations: Below Treeline.
Likelihood: Possible
Expected Size: 1 - 2