Avalanche Forecast

Issued: Apr 11th, 2016 8:48AM

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

triley, Avalanche Canada

Kootenay Boundary.

Spring Conditions. Forecast cloud cover, cooler air temperatures, and dropping freezing levels will all contribute to decrease the likelihood and size of avalanches. Avoid slopes that do not develop a solid crust overnight.

Summary

Weather Forecast

High cloud developing overnight with freezing levels dipping down to 2000 metres by morning. Mix of sun and cloud on Tuesday morning, becoming cloudy with moderate southwest winds in the afternoon. Freezing levels dropping to 1500 metres by Wednesday morning with moderate to strong southwest winds and 3-5 cm of new snow above 1500 metres. Cloudy with moderate winds during the day on Wednesday. Mix of sun and cloud on Thursday with overnight freezing down to 1300 metres.

Avalanche Summary

No new avalanches reported.

Snowpack Summary

Cornices are large, fragile, and could trigger deep slab avalanches that run to valley bottoms. Monitoring the overnight freeze of the snow surface is very important during the spring. If the snow surface does not freeze overnight or if the crust is only a few cm thick, the effect of daytime heating and solar radiation will weaken the snowpack much more quickly than it would if there is a well frozen thick crust. This is because the crust must first melt before the sun can weaken the snowpack. Low elevation and thin snowpack areas have become isothermal, meaning the snowpack is 0 degrees Celsius throughout. An isothermal snowpack is more prone to full depth wet slab avalanches during the heat of the day.

Problems

Cornices

The likelihood of natural cornice falls will drop as the cloud cover increases and the freezing levels drop.

Give cornices a wide berth when traveling on ridges. >Cornices become weak with daytime heating, so travel early on exposed slopes. >Pay attention to overhead hazards like cornices. >

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

Elevations: Alpine.

Likelihood

Possible

Expected Size

2 - 5

Loose Wet

Loose wet avalanche activity is expected to decrease with forecast cloud cover and descending freezing levels. Watch for slopes that do not re-freeze overnight.

Look for signs of surface instabilities such as pinwheeling and point releasing near cliffs. >Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet. >

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 3

Wet Slabs

Wet slab avalanche activity is expected to decrease with forecast cloud cover and descending freezing levels. Watch for slopes that do not re-freeze overnight.

Avoid rocky, shallow, and/or steep slopes during the heat of the day. >Be aware of the potential for large, deep avalanches.>

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Unlikely

Expected Size

2 - 5

Valid until: Apr 12th, 2016 2:00PM