Avalanche Forecast

Issued: Mar 16th, 2019 4:50PM

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

ghelgeson, Avalanche Canada

South Coast.

The heat is on and the game is changing. Direct sun and steadily warming temperatures are expected to destabilize the upper 20 to 30 cm of snow and a natural avalanche cycle is possible. Look up and avoid travel under avalanche paths and cornices.

Summary

Confidence

Low -

Weather Forecast

The first big warm up of the season really begins to flex on Sunday. Say goodbye to any kind of temperature driven overnight re-freeze for the next few days. This weather event is going to have a pretty significant impact on our snowpack.SATURDAY NIGHT: Freezing level rising to 2000 m, light northwest wind, no significant precipitation, no overnight re-freeze.SUNDAY: Clear skies, light northerly wind, freezing level rising to near 3000 m, no precipitation, no overnight re-freeze.MONDAY: Clear skies, light southeast wind, freezing level holding at 3000 m, no precipitation, no overnight re-freeze.TUESDAY: Clear skies, moderate southeast wind, freezing level holding at 3000 m, no precipitation, no overnight re-freeze.

Avalanche Summary

No new avalanche activity to report from the last few days.

Snowpack Summary

Wind slabs are likely done at this point, zapped of their strength by time and warming.For Sunday, we're most concerned about the upper 20 to 30 cm of snow that sits on crust on steep south slopes and possibly weak surface hoar crystals on sheltered and shaded slopes.The bigger questions are deeper in the snowpack. A layer of weak and sugary faceted grains sits on a melt-freeze crust about 50 to 120 cm deep. The layer is likely most prominent in the North Shore Mountains and on north aspects. After Saturday night, we're not expecting an overnight re-freeze for at least a few nights. That's going to allow the snowpack to warm and start freeing up a lot of water which acts like lubrication. When it doesn't freeze overnight, this process gets turbo-charged. How many hot days and warm nights will it take to wake up the more deeply buried weak layers? We're not sure, but now is probably a time to let the mountains do their thing from afar and check back in when the freezing level returns to seasonal norms which could happen by next weekend.

Problems

Persistent Slabs

Clear skies & warm temperatures are expected to destabilize the upper 20 to 30 cm of snow which could begin failing naturally. If you're going riding Sunday, go super early, seek out higher elevation shaded aspects and make an early exit.

Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.Back off slopes as the surface becomes moist or wet with rising temperatures.The likelihood of deep persistent slab avalanches will increase with each day of warm weather.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1.5 - 2.5

Loose Wet

Loose wet activity is expected to continue and the shaded aspects may start producing loose activity too, even at upper elevation. Cornices are going to begin to loosen up and you don't want to be under one of these monsters when they fail.

Avoid slopes when the solar radiation is strong, especially if they have large cornices overhead.Cornices become weak with daytime heating or solar exposure.Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Mar 17th, 2019 2:00PM