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Avalanche Canada jsmith, Avalanche Canada

Kootenay Boundary Avalanche Forecast

Apr 24th, 2019 3:37PM

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

Any appearance of the strong April sun can initiate a loose wet avalanche cycle. The likelihood of loose wet avalanches increases as temperatures warm through the day and/or if the sun comes out for a prolonged period of time.

Summary

Confidence

Low - Due to the number of field observations

Weather Forecast

WEDNESDAY NIGHT: Clear / Light, northwesterly winds / Alpine low -2 C / Freezing level 2000 m.

THURSDAY: Sunny / Light, southwesterly winds / Alpine high 6 C / Freezing level 2200 m.

FRIDAY: Cloudy with isolated alpine flurries; 1-3 cm / Light, westerly winds / Alpine high 6 C / Freezing level 2300 m.

SATURDAY: Cloudy with isolated alpine flurries; 1-3 cm / Moderate, southwesterly winds / Alpine high 2 C / Freezing level 1800 m.

Avalanche Summary

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

On Saturday, natural and skier triggered loose wet avalanches to size 1.5 were reported on all aspects at treeline and above.

Snowpack Summary

Rain to mountain-tops last week night soaked 20-40 cm of recent snow and initiated a loose wet avalanche cycle at treeline and above on Friday. Below treeline, the snow is isothermal (0 C throughout the snowpack) and disappearing rapidly.

As temperatures cool, we will enter a diurnal cycle during which the hazard will be low in the mornings, if there was a strong overnight freeze, and elevate throughout the day depending on warming and solar radiation. Hazard ratings are for the peak hazard expected during each day.

Problems

Loose Wet

If temperatures remain warm and the solar radiation is strong, loose wet avalanches in steep terrain are likely.

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

Aspects:

All aspects.

Elevations:

Alpine, Treeline.

Likelihood

Likely

Expected Size

1 - 2

Wet Slabs

If temperatures remain warm and the solar radiation is strong, wet slabs releasing on crust layers are still possible.

  • Pay attention to changing conditions with elevation/aspect.
  • If the snow is wet, mushy, or feeling bottomless, its time to go home.
  • Cornices become weak with daytime heating, travel early on exposed slopes.

Aspects:

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

Elevations:

Alpine, Treeline.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Apr 25th, 2019 2:00PM