Daytime warming may weaken cornices and sun-exposed slopes. Best to get off steep slopes before they moisten and watch your overhead exposure.
Summary
Confidence
Moderate - Uncertainty is due to how the snowpack will react to the forecast weather.
Weather Forecast
MONDAY NIGHT: Clear skies, 10 km/h west wind, alpine temperature -3 C.
TUESDAY: Clear skies, 10 km/h southwest wind, alpine temperature -1 C, overnight freeze and daytime freezing level rising to 1900 m.
WEDNESDAY: Clear skies, 10 km/h south wind, alpine temperature 0 C, overnight freeze and daytime freezing level rising to 2000 m.
THURSDAY: Mix of sun and cloud, 30 km/h south wind, alpine temperature 0 C, overnight freeze and daytime freezing level rising to 2000 m.
Avalanche Summary
A few small wet loose avalanches were observed out of steep sun-exposed terrain on Sunday. Similar activity is possible this week during a diurnal cycle.
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
- Extra caution is needed around cornices under the current conditions.
- 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.
Problems
Cornices
Cornices are large and looming along many ridgelines. Cornices may weaken during daytime heating, increasing the likelihood of being naturally triggered or failing from the weight of a human.
Aspects: North, North East, East, South East, North West.
Elevations: Alpine.
Likelihood
Expected Size
Loose Wet
Warm air temperature and periods of sunshine will increase the likelihood of triggering wet loose avalanches, particularly on solar aspects. Resulting avalanches are expected to be small, so the most likely place to get into trouble is in steep, extreme terrain.
Aspects: East, South East, South, South West, West.
Elevations: All elevations.
Likelihood
Expected Size
Valid until: Mar 16th, 2021 4:00PM
