Avalanche Forecast
Regions: Banff, Banff Yoho Kootenay, East Side 93N, Field, Kootenay, LLSA, Lake Louise, Sunshine, West Side 93N.
Another clear and sunny day is ahead. Although the radiant air temp is expected to be cool, expect South/West slopes to heat up and try to steer clear by mid-afternoon. Unfortunately, deep persistent slabs are still a possibility.
Confidence
High
Avalanche Summary
Sunshine patrol reported observing 2 size 2.5 deep slabs in the surrounding backcountry. One on Fatigue Mountain and one near Mt. Ball. Both occurred within the last 24 hours. Lake Louise patrol reported triggering two old hard wind slabs size 1.5 in the White Horn gullies with explosives. No other avalanches were observed or reported.
Snowpack Summary
Little change. Above 1600 m the surface is 10-20 cm of soft, settled snow with minimal wind effect. Suncrusts are forming on steep solar slopes and are more widespread below 1400 m. The middle of the snowpack holds several crust layers that continue to produce avalanches, and the base of the snowpack is very weak depth hoar in almost all areas.
Weather Summary
On Wednesday, alpine temperatures will remain cool with highs at about -6. The valley, however, could climb to 5 degrees. Freezing levels up to 2000m. Skies are expected to be clear, so expect solar radiation to be a factor on South and West aspects late in the day. The wind could come up to the moderate range from the West.
Terrain and Travel Advice
- Uncertainty is best managed through conservative terrain choices at this time.
- Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
Avalanche Problems
Deep Persistent Slabs
The weak depth hoar at the bottom of the snowpack inspires little confidence. Multiple parties have remotely triggered large slabs from thin areas in the snowpack. Give careful consideration to the slopes overhead as large avalanches may run well into the runout zone or into lower-angle terrain. Avoid big terrain features and be especially cautious in thin or rocky areas, where triggering is more likely.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 2 - 4
Persistent Slabs
Three persistent weak layers formed in January are down 40-110 cm. Buried sun crusts on steep solar slopes present the greatest concern for triggering, however, weak facets and isolated surface hoar can be found on the same interfaces on shaded aspects.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Unlikely - Possible
Expected Size: 1.5 - 3
Loose Wet
Clear skies and sunshine will produce wet avalanches on sun-exposed slopes late in the day. Rocky areas often increase this heating and low elevations may also be susceptible to this problem on Wednesday.
Aspects: South, South West, West.
Elevations: All elevations.
Likelihood: Likely
Expected Size: 1 - 1.5