Avalanche Forecast
Issued: Mar 29th, 2021 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Storm Slabs.
swerner,
Avalanche Canada
Recent storm snow accompanied by strong wind has formed storm slabs that may be reactive and easily triggered by the weight of a skier or rider. These may be extra sensitive in wind-loaded areas at upper elevations.
Summary
Confidence
Moderate - Uncertainty is due to the extreme variability of wind effect on the snowpack. Uncertainty is due to how quickly the snowpack will recover and gain strength.
Weather Forecast
Another Pacific frontal system is due to arrive Wednesday bringing snow at upper elevations and strong wind.Â
Tuesday: A mix of sun and cloud. Ridgetop wind strong from the northwest. Freezing levels 400 m.
Wednesday: Mix of sun and cloud. Ridgetop wind strong from the southwest. Alpine temperatures near -6 and freezing levels 1000 m.Â
Thursday: A mix of sun and cloud with light snow amounts. Ridgetop wind light from the southwest and freezing levels 900 m.
Avalanche Summary
There are no recent reports of avalanche activity.
Avalanche size and sensitivity are expected to decrease over the next few days, however, reactive storm slabs are still anticipated, especially in wind-loaded slopes at upper elevations. If the sun comes out on Tuesday, it could quickly trigger natural avalanches within the new snow.Â
Cornices are large at this time of year, and they become weaker when the sun hits them.
Snowpack Summary
15-35 cm of snow has fallen in the region over the weekend. This was accompanied by strong southwest to northwest wind. Fresh wind slabs may exist on most slopes due to changing wind directions. At lower elevations, much of this precipitation fell as rain below treeline. The lower elevations are now showing a firm surface crust.
Buried 70-120 cm deep, a spotty layer of surface hoar may exist on sheltered north aspects, as well as a crust on south aspects and below 1450 m. Recent observations suggest that this interface is bonding.
The mid and lower snowpack is reported as well settled and strong in most areas. However, weak facets exist at the base of the snowpack in the more shallow snowpack zones within much of the region and have the potential to be triggered on steep, rocky slopes with a shallow or thin to thick snowpack; especially with large loads such as a cornice fall.
Terrain and Travel
- Continue to make conservative terrain choices while the storm snow settles and stabilizes.
- Avoid freshly wind loaded terrain features.
- Even brief periods of direct sun could produce natural avalanches.
- Look for signs of instability: whumphing, hollow sounds, shooting cracks, and recent avalanches.
- Be aware of highly variable recent wind loading patterns.
Problems
Storm Slabs
Fresh and reactive storm slabs are likely to be encountered, especially in wind-loaded areas at upper elevations. A change in wind direction means that wind loading may be found on many aspects.
Keep in mind that brief periods of sun can initiate natural avalanches, especially in areas that saw high snowfall amounts.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Mar 30th, 2021 4:00PM
