The danger will be LOW when a thick melt-freeze crust is on the snow surface and increase during the heat of the day as warm air and sun weaken the snow surface. Best to get off steep slopes before they moisten and watch your overhead exposure.
Summary
Confidence
Weather Forecast
WEDNESDAY NIGHT: Clear skies, 20 km/h south wind, alpine temperature 0 C, freezing level 2200 m but snow-surface freeze is likely.
THURSDAY: Clear skies in the morning and afternoon cloud, 30 km/h south wind, alpine temperature 1 C, freezing level 2300 m.
FRIDAY: Cloudy with rain switching to snow, accumulation 10 to 20 cm above the rain-snow line, 20 to 40 km/h southwest wind, alpine temperature -3 C, freezing level lowering to 1500 m.
SATURDAY: Mix of sun and cloud, 20 km/h southwest wind, alpine temperature -5 C.
Avalanche Summary
No new avalanches were observed on Wednesday, with the exception of small loose wet avalanches out of steep sun-exposed terrain in the afternoon. Similar activity is possible during this diurnal cycle period.
Snowpack Summary
We are in the midst of a diurnal cycle, where the snow surface will freeze into a melt-freeze crust at night and moisten during daytime heating, particularly on sun-exposed slopes. Dry, settled snow may still exist near the mountain tops on northerly aspects. Cornices are large and always have the potential of failing, particularly during daytime warming.
Deeper in the snowpack, a persistent weak layer from late January is buried around 80 to 150 cm and is composed of a combination of surface hoar, facets, and crusts. We haven't received a report of avalanche activity on this layer since late February. The likelihood of triggering this layer is low during the current diurnal cycle, with a thick melt-freeze crust expecting to form each night.
As always, best to avoid shallow, rocky areas where a weak and faceted snowpack may be found.
Terrain and Travel
- A moist or wet snow surface, pinwheeling and natural avalanches are all indicators of a weakening snowpack.
- When a thick, melt-freeze surface crust is present, avalanche activity is unlikely.
- Extra caution is needed around cornices under the current conditions.
Problems
Loose Wet
Warm air temperature and sunshine will increase the likelihood of triggering wet loose avalanches, particularly on steep, sun-exposed slopes. Resulting avalanches are expected to mostly be small, so the most likely place to get into trouble is in extreme terrain.
Aspects: East, South East, South, South West, West.
Elevations: All elevations.
Likelihood
Expected Size
Cornices
Cornices are large and looming along many ridgelines. Cornices may weaken during daytime heating, increasing the likelihood of triggering naturally or failing from the weight of a human.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Valid until: Mar 18th, 2021 4:00PM
