Avalanche Forecast

Issued: Mar 31st, 2017 4:14PM

The alpine rating is considerable, the treeline rating is considerable, and the below treeline rating is moderate. Known problems include Storm Slabs, Loose Wet and Cornices.

triley, Avalanche Canada

Lizard-Flathead.

Avalanche Danger is slowly trending down. The snowpack has seen a lot of change in the last few days, and it may need another day to adjust. Conservative terrain choices are recommended.

Summary

Confidence

Moderate - Freezing levels are uncertain on Saturday

Weather Forecast

Overnight: Cloud developing overnight that will keep the freezing level close to 2000 metres. Saturday: Overcast with flurries or light snow combined with moderate westerly winds and daytime freezing around 2100 metres. Sunday: A cooler day with a mix of sun and cloud. Moderate westerly winds and freezing around 1500 metres. Monday: Re-freeze to valley bottom expected. Chance of snow developing from the northeast.

Avalanche Summary

Numerous storm slab avalanches up to size 2.5 reported from explosives control on Friday, as well as loose wet avalanches released by ski cuts up to size 1.5. Numerous storm slab and loose wet avalanches were reported from the Fernie area on Thursday. One natural cornice fall was size 3.0, and pulled a storm slab from the slope below. There is concern for storm slabs to continue to be reactive to human triggering if there is little or no re-freeze before another warm day on Saturday.

Snowpack Summary

Storm slabs in the alpine received a big punch of solar radiation on Friday. Sheltered slopes may continue to be dry and may not be well bonded to the old surface. At treeline and below the snow is moist or wet, and may not get a good re-freeze overnight before another forecast warm day with high freezing levels. The deep persistent weak layer of facets and crust that was buried early in the winter may "wake-up" due to this prolonged warming and recent loading. This deep problem is difficult to forecast, and the best strategy may be to avoid large terrain features until the snowpack cools and adjusts to the recent inputs (ie loading, sun, wind, and temperature fluctuations).

Problems

Storm Slabs

Recent storm slabs may continue to be reactive to human triggering. This is most likely in shaded alpine areas where the snow may be drier.

The new snow will require several days to settle and stabilize.Be wary of slopes that did not previously avalanche.

Aspects: North, North East, East, South East.

Elevations: Alpine, Treeline.

Likelihood

Likely

Expected Size

2 - 3

Loose Wet

The snow may become moist or wet early in the day if there is not a good re-freeze overnight.

Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 2

Cornices

Cornices may continue to be weak and naturally shed the recent cornice growth. Cornice falls may release storm slab avalanches on the slopes below.

Do not travel on slopes that are exposed to cornices overhead.Pay attention to overhead hazards like cornices which could easily trigger deep slabs.

Aspects: North, North East, East, South East, South.

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

2 - 3

Valid until: Apr 1st, 2017 2:00PM