Avalanche Canada jsmith, Avalanche Canada

Cariboos Avalanche Forecast

Apr 23rd, 2019 4:05PM

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

Lingering wind slabs may still be reactive to human triggers; especially on lee features below alpine ridgetops.

Summary

Confidence

Moderate - Due to the number of field observations

Weather Forecast

TUESDAY NIGHT: Mostly cloudy with isolated alpine flurries; 1-3 cm / Light, northwesterly winds / Alpine low -6 C / Freezing level 1200 m.

WEDNESDAY: Mix of sun and cloud / Moderate, northwesterly winds / Alpine high -2 C / Freezing level 1500 m.

THURSDAY: Sunny / Light, westerly winds / Alpine high 0 C / Freezing level 1700 m.

FRIDAY: Cloudy with isolated alpine flurries; 1-3 cm / Light, southerly winds / Alpine high -1 C / Freezing level 1700 m.

Avalanche Summary

No new avalanches were reported in this region on Monday. However, there are currently very few professional observers submitting daily observations. Please submit your observations to the MIN. Photos of avalanches or current conditions are particularly useful.

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

Possible

Expected Size

1 - 2

Lingering wind slabs may still be reactive to human triggers; especially on lee features below alpine ridgetops.

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

Aspects:

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

Elevations:

Alpine.

Loose Wet

An icon showing Loose Wet

Likelihood

Possible

Expected Size

1 - 2

Strong solar radiation may trigger loose wet avalanches on steep terrain; especially at upper elevations where there is new snow.

  • A moist/wet snow surface, pinwheeling and natural avalanches all indicate a weakening snowpack.
  • Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.

Aspects:

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

Elevations:

Alpine, Treeline.

Valid until: Apr 24th, 2019 2:00PM