Avalanche Forecast

Issued: Apr 18th, 2016 3:00PM

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

triley, Avalanche Canada

Northwest Coastal.

Spring Conditions. The storm is over, however wind slabs left behind may be easy to trigger at higher elevations. Watch for a rapid change to sunny and hot conditions. Areas with new snow may release naturally when the sun comes out.

Summary

Weather Forecast

Clearing overnight with light northeast winds replacing the strong southwest winds during the storm. Freezing levels down to 500 metres overnight and then rising up to 2500 metres on Tuesday under clear skies and strong solar radiation. Clear and sunny on Wednesday with freezing level at 2500 metres. Clear and sunny on Thursday, some chance that the ridge of high pressure will break down during the day resulting in high cloud.

Avalanche Summary

Wet slab avalanches releasing down to the ground have been reported along the highway corridor near Stewart from mid-elevation paths. Wind slabs and cornice falls are suspected in the high alpine, but visibility has been poor and we have no new reports from alpine elevations.

Snowpack Summary

There has been 20-40 mm of precipitation in the past few days. Most of this has fallen as rain up to at least 1500 metres. Most of the precipitation has been in the near coastal ranges, with Stewart and Kitimat receiving closer to 40mm and areas around Terrace closer to 20mm. Winds have been strong out of the south; reports from Stewart of gusts above 100 km/hr on Monday that have developed wind slabs in the high alpine. Rain has soaked the snowpack at lower elevations. Some recent crusts within the upper snowpack may continue to provide a sliding layer for loose wet avalanches when forecast temperatures and freezing levels spike in the next few days.

Problems

Wind Slabs

New wind slabs are expected to have formed during the recent storm at high alpine elevations where it was cold enough for snow. Forecast sun and high freezing levels may result in natural avalanches.

Be alert to conditions that change with elevation.>Avoid freshly wind loaded features.>Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.>

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

Elevations: Alpine.

Likelihood

Likely - Very Likely

Expected Size

1 - 4

Wet Slabs

Wet slab avalanches have been triggered by recent rain events. Forecast sun and high freezing levels may continue to trigger weak wet snowpacks if there is no re-freeze overnight.

Be aware of the potential for large, deep avalanches.>Plan to be off big slopes before the temperatures rises and the snowpack deteriorates.>

Aspects: North, North East, East.

Elevations: Alpine, Treeline.

Likelihood

Possible

Expected Size

2 - 5

Loose Wet

Forecast strong solar radiation, warm temperatures and high freezing levels may continue to result in loose wet avalanches. Monitor crust thickness and strength throughout the day.

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

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

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1 - 3

Valid until: Apr 19th, 2016 2:00PM