Avalanche Forecast
Regions: Little Yoho.
Warm temperatures are expected to persist into Monday, limiting the overnight refreeze of the upper snowpack. Monitor local conditions and minimize exposure to bigger terrain until things cool off.
The hazard is expected to improve on Tuesday with cooler temperatures.
Confidence
Moderate
Avalanche Summary
Solar-triggered natural avalanches up to size 2 were occurring in steep terrain as the day heated up on Sat/Sun, occasionally gouging down into the lower snowpack.
Several cornice failures have also been observed later in the day, occasionally triggering slabs up to size 2.
Snowpack Summary
Light wind effect in the alpine. On alpine north aspects 15-30 cm of dry settled snow sits over the Mar 27 crust that exists to ~2500 m. On solar aspects sun crusts are present to ridgetop with moist snow later in the day. A supportive surface crust exists in most places below treeline.
70-130 cm of firm snow sits over the January facet layer which remains a concern in thin areas. The lower snowpack is generally well consolidated. Treeline snowpack depths range from 150 to 250 cm.
Weather Summary
Air temps and solar inputs are key things to pay attention to as we move into spring.
Sunday night: Becoming cloudy. Alpine temps remain near 0°C with minimal refreeze overnight. Ridge wind light to 25 km/h. Freezing level staying around 2400 m.
Monday: Mainly cloudy with light precip beginning in the late afternoon. SW winds in the moderate range. Treeline temps near +2°C with freezing levels staying around 2400 m.
Terrain and Travel Advice
- Avalanche danger will increase as the surface crust breaks down.
- Avoid steep, sun-exposed slopes when the air temperature is warm or when solar radiation is strong.
- Start your day early and be out of avalanche terrain during the heat of the day.
- Be mindful that deep instabilities are still present and have produced recent large avalanches.
Avalanche Problems
Loose Wet
As the surface crusts break down and temps stay warm, wet slabs, sluffing off of steep faces, and triggering deeper instabilites becomes more likely. Monitor local conditions for the overnight refreeze and minimize exposure to steep terrain if the surface snow does not freeze well on Monday.
Aspects: East, South East, South, South West, West.
Elevations: All elevations.
Likelihood: Possible - Likely
Expected Size: 1 - 2
Persistent Slabs
Below the recent snow, a 90-150 cm slab sits on the weak Jan 30 facet layer. On all but high north aspects, recent sun crusts and the March 27 rain crust cap this slab, providing some security. Continue to use caution in thinner, high areas or when these crusts are weak or breaking down with daytime heat.
Aspects: All aspects.
Elevations: Alpine, Treeline.
Likelihood: Possible
Expected Size: 2 - 3