Avalanche forecast

Northwest Inland

Mar 14 – 15, 2017Avalanche Canada
View on map
Archived · expired 10 years ago

Avalanche danger

Thu
Fri
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
Open full map

Highlights

Stormy weather continues to keep the avalanche danger elevated. Watch for deep pockets of wind transported snow at higher elevations.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible - Likely
    Size
    2–3
    A reactive slab has possibly formed above a weak layer of crusts, facets, and surface hoar that formed in February. This weak layer may be spotty and confined to terrain that is sheltered from the wind.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1–2
    Storm slabs are expected to continue to develop due to forecast new snow and wind. Watch for the transition to moist or wet snow as you descend in elevation.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely - Possible
    Size
    2–3
    A lingering weakness at the bottom of the snowpack may reawaken with the load of the new snow and warming. It'll be most reactive in thin rocky start zones and shallow snowpack locations.

Confidence

Moderate - Forecast snowfall amounts are uncertain on Wednesday

Weather Forecast

Overnight: Freezing level dropping to valley bottoms, and 3-5 cm of new snow combined with strong southwest winds. Wednesday: Moderate southwest winds, daytime freezing level around 700 metre, and flurries or periods of light snow. Thursday: Moderate southerly winds, freezing at valley bottoms, and 3-5 cm of new snow. Friday: Moderate southerly winds, freezing level at valley bottoms, and 3-5 cm of new snow.

Avalanche Summary

Numerous natural avalanches up to size 2.5 were reported from the west of the region in the Howson's.

Snowpack Summary

Storm slabs continue to build with each pulse of snow and wind. Warm temperatures will make touchy slabs at higher elevations and unstable wet snow at lower elevations. A weak interface that was buried in late February may finally have enough snow above it to form a reactive slab. The interface is composed of facets, crusts, and surface hoar and may be 40-80 cm deep. There's uncertainty about the distribution and reactivity of this interface. The mid-pack is well consolidated and sits above weak sugary snow near the ground. The deeper basal weakness remain a concern in thin rocky start zones and shallow snowpack locations.

Regions covered