Avalanche Forecast

Issued: Apr 16th, 2022 4:00PM

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

Avalanche Canada wlewis, Avalanche Canada

Danger ratings are low, but always be on the lookout for wind slabs at higher elevations and weak overhanging cornices.

Watch for strong sunshine creating wet surface snow on south facing terrain features. 

Summary

Confidence

Moderate - Uncertainty is due to the timing or intensity of solar radiation and its effect on the snowpack. Uncertainty is due to the fact that cornice falls are particularly difficult to forecast.

Weather Forecast

SATURDAY NIGHT: Cloudy with light southeasterly winds. 2-10 cm of snow expected. Freezing levels drop to 500 m. 

SUNDAY: A mix of sun and cloud with moderate southeasterly winds. Freezing levels rise to 1500 m. Isolated flurries are expected to bring trace amounts. 

MONDAY: Snow begins early in the morning with 10-15 cm expected, freezing levels reach 1400 m. Strong southeast winds. Snow continues overnight, 10-20 cm expected.

TUESDAY: Cloudy with continued light snowfall bringing up to 5 cm over the day. Freezing levels reach 1300 m. Moderate to strong southerly winds. 

Avalanche Summary

On Friday size 2.5 natural slab avalanche was reported on a northeast aspect. This occurred in a steep cross-loaded terrain feature and was possibly triggered by strong sunshine. Small wind slabs were also rider triggered on Friday in wind affected terrain. 

Several cornice falls have been observed over the last week, affected by brief periods of strong sunshine. On Thursday, a cornice fall produced a size 3 slab avalanche on a northeast slope. This avalanche failed on a deep weak layer within the snowpack, which is considered unlikely to occur from human or natural triggers at this time - except for large cornice falls. 

Sunshine also triggered small wet avalanches throughout the week, on steep south facing features. 

Snowpack Summary

Spring convection has delivered highly variable amounts of storm snow above a melt freeze crust found on sun affected slopes. Periods of sun may soften or break down the crust throughout the day where it exists on the surface. Wind affected snow can be found mainly on west facing slopes at treeline and above, from recent easterly winds. However local wind patterns may have varied.

A widespread and supportive crust is buried 10-40 cm deep. Reports suggest this crust is currently bonding well with the layers around it. 

Various melt-freeze crusts exist in the upper to middle snowpack, which reports suggest are bonding well. The lower snowpack is considered strong and well settled at this time. 

Terrain and Travel

  • Pay attention to cornices and give them a wide berth when traveling on or below ridges.
  • Be careful as you transition into wind affected terrain.
  • Carefully evaluate steep lines for wind slabs.
  • Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet

Problems

Wind Slabs

An icon showing Wind Slabs

Pockets of wind slabs may be found at higher elevations from recent easterly winds. Watch for wind affected snow near ridgelines and around mid slope rollovers.

Weak cornices may also be found on many aspects. Cornice falls are more likely as temperatures warm each day, or when strong sunshine is present.

Aspects: North, South West, West, North West.

Elevations: Alpine.

Likelihood

Possible - Likely

Expected Size

1 - 2

Loose Wet

An icon showing Loose Wet

Wet avalanches become more likely as strong sunshine weakens the snowpack. 

Watch for rapidly changing conditions, avalanche hazard will increase as surface snow becomes moist or wet. Minimize your exposure to sun affected slopes even during brief periods of strong sunshine. 

Aspects: East, South East, South, South West, West.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 2

Valid until: Apr 17th, 2022 4:00PM