Avalanche Forecast
Issued: Jan 17th, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Persistent Slabs and Deep Persistent Slabs.
shorton,
Avalanche Canada
Continue to make conservative terrain choices and consider the consequences of an avalanche on a chosen slope. The snowpack remains weak and untrustworthy.
Summary
Confidence
Moderate
Avalanche Summary
A few small (size 1 to 1.5) human triggered slabs were reported on Monday, mostly failing on a 30 cm deep surface hoar layer. A few larger (size 2) human triggered slabs were reported in the Esplanade range. Explosive avalanche control produced multiple large (size 2) and one very large (size 3) deep persistent slab avalanches along steep rocky ridges at treeline. On Saturday, a skier triggered a size 2.5 avalanche on a low angle alpine slope near Golden. This avalanche had a 1 m crown and ran on the facets near the bottom of the snowpack.
Snowpack Summary
10 to 20 cm of settled storm snow can be found in sheltered areas, while open terrain has been wind affected. A rain crust can be found up to 2000 m in most parts of the region.
There are two concerning weak layers in the top meter of the snowpack. The first is a layer of surface hoar from early January and the second is a layer of surface hoar, facets, and a crust from December. Both these layers are most concerning at treeline and above. There is also a layer of large facets at the bottom of the snowpack that continues to produce avalanches and will likely persist for a prolonged period of time.
In general, the snowpack is shallow and weak.
Weather Summary
Tuesday night
Cloudy, no precipitation, 20 km/h west wind, treeline temperatures drop to -8 °C.
Wednesday
Cloudy, no precipitation, 30 to 40 km/h southwest wind, treeline temperatures around -6 °C.
ThursdayMostly cloudy, isolated flurries with 1 to 5 cm of snow, 40 km/h southwest wind, treeline temperatures around -6 °C.
FridayMostly sunny skies, 30 km/h northwest wind, treeline temperatures around -8 °C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Be mindful that deep instabilities are still present and have produced recent large avalanches.
- Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
- Carefully assess open slopes and convex rolls where buried surface hoar may be preserved.
- Uncertainty is best managed through conservative terrain choices at this time.
Problems
Persistent Slabs
There are two concerning weak layers in the top meter of the snowpack that continue to produce human triggered avalanches. The first is a layer of surface hoar down 30 to 40 cm buried in early January. The second is a layer of surface hoar, facets and/or a crust from December. This layer can be found down 40 to 70 cm.
Aspects: All aspects.
Elevations: All elevations.
Likelihood
Expected Size
Deep Persistent Slabs
A weak layer near the base of the snowpack, buried in November, remains a concern. Human triggering of this layer remains possible, especially in shallow areas with variable snow depths.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood
Expected Size
Valid until: Jan 18th, 2023 4:00PM
