Avalanche Forecast

Issued: Feb 18th, 2020 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 mconlan, Avalanche Canada

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As you travel, be observant for moistening snow on sun-exposed slopes and for lingering wind slabs.

Summary

Confidence

High - Confidence is due to a stable weather pattern; little change is expected for several days.

Weather Forecast

TUESDAY NIGHT: Clear skies, light northeast wind, alpine temperature -4 C, freezing level 500 m.

WEDNESDAY: Clear skies, light south wind, alpine temperature -2 C, freezing level 1500 m.

THURSDAY: Clear skies, light to moderate southwest wind, alpine temperature -4 C, freezing level 1300 m.

FRIDAY: Increasing clouds, moderate southwest wind, alpine temperature -5 C, freezing level 1000 m.

Avalanche Summary

Small wind slabs and wet loose avalanches were triggered naturally and by humans on Monday. The wind slabs generally occurred on northerly aspects and the wet loose avalanches on southerly aspects.

With clearing skies gave views of the surrounding mountains. Numerous people reported slab avalanches in the Spearhead Range. The avalanches were far away but could have released on the basal instability described in the Snowpack Summary.

Snowpack Summary

Clear skies have formed a melt-freeze crust on sun-exposed aspects, which will moisten during daytime heating. Soft snow should prevail on shaded aspects, which overlies hard surfaces and potentially surface hoar in sheltered terrain around treeline. Isolated wind slabs may still linger in steep, lee terrain features in the alpine.

The midpack is well-settled. Faceted snow and crusts exist near the base of the snowpack in much of the region. Avalanche activity was recently noted on Curtain Glacier in the Spearhead Range, although it is unclear if the avalanches released on this basal instability. This layer is largely dormant at the moment but appears to be most likely a problem on the eastern side of the region, in alpine terrain, and where there is relatively smooth ground (e.g., glaciers, scree slopes, rock slabs).

Terrain and Travel

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

Problems

Wind Slabs

An icon showing Wind Slabs

Wind slabs may linger in steep, alpine terrain. The slabs have been reported as being hard immediately adjacent to ridges.

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

Elevations: Alpine.

Likelihood

Unlikely - Possible

Expected Size

1 - 2

Loose Wet

An icon showing Loose Wet

Sun-exposed slopes will warm up with daytime heat. Wet loose avalanches could sweep you off your feet and push you into terrain traps, such as gullies or cliffs. Cornices will also weaken during the day. Stand well back of them on ridges and avoid travelling beneath them.

Aspects: South East, South, South West.

Elevations: All elevations.

Likelihood

Possible

Expected Size

1 - 1.5

Valid until: Feb 19th, 2020 5:00PM