Avalanche Forecast

Issued: Mar 17th, 2019 4:56PM

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

Avalanche Canada ghelgeson, Avalanche Canada

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The heat is on and the game is changing. Direct sun and increasingly warm temperatures are expected to destabilize the upper 10 to 40 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

Hot days & warm nights look to be with us through at least Thursday. We're not expecting any kind of substantive re-freeze for the foreseeable future.SUNDAY NIGHT: Light east/southeast wind, freezing level 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, light to moderate southeast wind, freezing level holding around 3000 m, no precipitation, no overnight re-freeze.WEDNESDAY: Clear skies, light southeast wind, freezing level around 2600 m, no precipitation, no overnight re-freeze.

Avalanche Summary

On Sunday a few large avalanches were reported on solar aspects up the Railroad/Hurley Pass. On Saturday natural avalanches to size 2 were reported from solar aspects and several north aspects produced natural avalanches to size 1.5. As we enter a period of increased warming it's worth reminding ourselves that glide cracks are to be avoided at all times. They're incredibly unpredictable and when they fail, they often fail big. Glide avalanche concerns are especially important to consider in the Coquihalla area. A recent social media post from a professional in this part of the region does a great job of highlighting the issue. (Link here) A glide failed naturally on a southeast facing slope around 1000 m on Saturday.On Friday a skier triggered a small wind slab at treeline that resulted in a broken leg. A few small wind slabs were observed on north facing alpine terrain and some natural cornice failure is beginning to be be observed too.

Snowpack Summary

Light amounts of new snow have been redistributed by southwesterly and northerly winds, potentially creating some unusual wind slabs, including on south-facing slopes. Beneath this recent snow you may find hard wind-affected snow at higher elevations, soft and faceted snow in shaded and sheltered areas, and melt-freeze crusts on southerly slopes. The middle and lower snowpack is generally well-settled. For Monday, we're most concerned about the upper 10 to 40 cm of snow.There may be bigger questions deeper in the snowpack. We're not expecting an overnight re-freeze for the forseeable future. That's going to allow the snowpack to warm which starts freeing up a lot of water which lubricates the upper snowpack. It also allows the upper snowpack to start creeping downhill at an accelerated rate. When it doesn't freeze overnight, this process gets turbo-charged. Could multiple hot days and warm nights wake up deeply buried weak layers that we haven't thought about for awhile? 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

Wind Slabs

An icon showing Wind Slabs
A warm night followed by another day of clear skies & hot temperatures is expected to further destabilize the upper 10 to 40 cm of snow which has potential to fail naturally.
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.Be careful with wind loaded pockets, especially near ridge crests and roll-overs.

Aspects: All aspects.

Elevations: Alpine, Treeline.

Likelihood

Possible - Likely

Expected Size

1.5 - 2.5

Loose Wet

An icon showing 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.Loose avalanches may start small but they can grow and push you into dangerous terrain.

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Likely

Expected Size

1 - 2

Valid until: Mar 18th, 2019 2:00PM

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