Avalanche Canada jsmith, Avalanche Canada

Cariboos Avalanche Forecast

Apr 22nd, 2019 4:51PM

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

New snow and moderate winds Monday night may create small wind slabs that when in motion, step-down to the recent storm snow, resulting in large avalanches.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

MONDAY NIGHT: Cloudy with flurries; 5-10 cm. / Moderate, southwesterly winds / Alpine low -3 C / Freezing level 1500 m.

TUESDAY: Cloudy with isolated flurries; 2-5 cm / Light, westerly winds / Alpine high -1 C / Freezing level 1800 m.

WEDNESDAY: Sunny / Light to moderate, westerly winds / Alpine high -2 C / Freezing level 1500 m.

THURSDAY: Mostly sunny / Light, westerly winds / Alpine high -1 C / Freezing level 1700 m.

Avalanche Summary

On Sunday, numerous solar triggered avalanches initiating below alpine ridgetops up to size 3 were reported.

Check out this MIN report of a notable human triggered size 2.5 avalanche that occurred on Saturday HERE.

On Friday, a widespread storm slab natural avalanche cycle to size 3 occurred on all aspects in the alpine. This new snow will need several days to settle and bond to the old snow surface.

Snowpack Summary

10-25 mm of rain soaked the snowpack below treeline. The rain/snow boundary on Friday was around 2000 m. Strong southwesterly winds heavily loaded lee aspects. New snow amounts in the alpine will taper rapidly with elevation and likely equate to around 10-20 cm of moist snow at upper elevations adding to the 15-40 cm recent snow which overlies a crust everywhere except high elevation, north facing terrain where preserved surface hoar (weak, feathery crystals) may be present in isolated locations down 40-60 cm. A similar layer buried in early April is down 50-80 cm. Smaller storm slab avalanches may step down to one of these deeper weak layers.

Below treeline, snow is disappearing rapidly.

Problems

Wind Slabs

An icon showing Wind Slabs

Likelihood

Likely - Possible

Expected Size

1 - 2

New snow and moderate winds Monday night may create small wind slabs that when in motion, ‘step-down’ to the recent storm snow, resulting in large avalanches.

  • Use small slopes without consequence to test the bond of the recent snow.
  • Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
  • Pay attention to changing conditions with elevation/aspect.

Aspects:

North, North East, East, South East, North West.

Elevations:

Alpine, Treeline.

Valid until: Apr 23rd, 2019 2:00PM