Avalanche forecast

Northwest Inland

Apr 18 – 19, 2023Avalanche Canada
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Avalanche danger

Thu
Fri
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Fresh wind slabs may be reactive to human triggers on leeward slopes in the alpine. Whumfing, shooting cracks and natural avalanches are indicators of an unstable upper snowpack.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    Fresh wind slabs may be reactive to human triggers on lee aspects in the alpine.

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    1–1.5

    Even short periods of strong solar radiation may trigger wet loose avalanches on steep, sunny slopes.

Confidence

Low

Avalanche Summary

A fresh thin wind slab size 1 was reported on Tuesday.

Observations are limited at this time of year, please consider sharing any information or photos you have on the Mountain Information Network to help guide our forecasts.

Snowpack Summary

20-40 cm of snow last week accompanied by south winds formed wind slabs on northerly aspects. The snow sits over wind-affected surfaces or a crust on south-facing slopes.

A weak layer buried in late March is down 30-50 cm and exists as surface hoar and facets on north facing slopes and a crust elsewhere. Test results showed that this layer may be reactive to human triggers in isolated locations where the layer is well-preserved and has a cohesive overlying slab. See MIN.

The middle of the snowpack is strong and contains numerous hard crusts. Near the ground, weak faceted crystals exist. There hasn't been avalanche activity on this layer recently, but it remains on our radar and may become active when we experience change, such as rapid loading (heavy snowfall or rain) or prolonged warming.

Weather Summary

Tuesday Night

Cloudy with 5-15 cm of new snow. Ridgetop winds 10-30 km/h from the south. Treeline temperatures near -5 and freezing level at valley bottom.

Wednesday

A mix of sun and cloud with isolated flurries. Ridgetop wind 20-40 km/h from the southeast. Treeline temperatures near -2 C and freezing level 1300 m.

Thursday

Mix of sun and cloud. Ridgteiop wind 30 gusting to 65 km/h from the southeast. Treeline temperatures near -2 C with freezing levels near 1400 m.

Friday

Cloudy with new snow 3-10 cm. Ridgetop wind 15-45 km/h from the southeast. Treeline temperatures near -2 C with freezing levels near 1400 m.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Back off slopes as the surface becomes moist or wet with rising temperatures.
  • Wind slabs may be poorly bonded to the underlying crust.
  • Avoid steep, rocky, and wind effected areas where triggering slabs is more likely.
  • Cornice failure may trigger large avalanches.
  • Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.

Regions covered