Avalanche Forecast
Issued: Mar 21st, 2023 4:00PM
The alpine rating is , the treeline rating is , and the below treeline rating is Known problems include Deep Persistent Slabs, Persistent Slabs and Loose Wet.
AB,
Avalanche Canada
A stronger and deeper snowpack exists in the Yoho zone. Remain watchful for daytime heating and exposure to large triggers above slopes, such as cornices.
Summary
Confidence
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
Above 1600 m the surface is 10-25 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 weak facets that appear their strongest in deep snowpacks such as in Little Yoho.
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.
Problems
Deep Persistent Slabs
The weak depth hoar at the bottom of the snowpack inspires little confidence. We have seen increased activity on this layer through the week in most areas of the forecast region with the exception of the deeper snowpack areas around Little Yoho. 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
Expected Size
Persistent Slabs
Three persistent weak layers formed in January are down 60-120 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
Expected Size
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
Expected Size
Valid until: Mar 22nd, 2023 4:00PM
