Avalanche forecast

Jasper

Apr 23 – 24, 2023Avalanche Canada
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Avalanche danger

Tue
Wed
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
No rating
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Highlights

Sunday night is expected to have less of an overnight freeze than previous nights and Monday may start warm. The thick high clouds potentially will hold onto the warm air overnight. If Monday starts warm, this could increase the reactivity of cornices and deep persistent slabs.

Avalanche problems

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–3

    With increasing daytime temperatures and sun effect, mature cornices have a potential to trigger the lingering deep persistent slab below.

  • Loose Wet

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

    There is expected to be less of a freeze Sunday night and Monday the freezing level will be 2300m or higher depending on weather variables.

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–4

    The bottom of the snowpack is inherently weak with well-developed Facets and Depth Hoar.

Confidence

Moderate

Avalanche Summary

There was an avalanche Fatality in Banff Park near Lake Louise Saturday from a deep large human triggered slide. On Friday, 2 natural large deep avalanches were observed, both on East aspect in the alpine triggered by a cornice failure.

Maligne road patrol saw no new natural avalanche activity on Friday.

Post avalanche observations to the MIN.

Snowpack Summary

10cm of new snow from last week has settled onto sun crusts on solar aspects with a melt-freeze crust below tree line. Old wind slab is on exposed alpine terrain.

A weak layer of sun crust or facets lingers in the mid-pack but the main concern is the depth hoar and basal facets at the bottom of the snowpack causing our deep persistent slab problem.

Weather Summary

Parkers ridge weather on Monday will bring sun and cloud, no new snow, high of 1 °C, light winds, and 2400m freezing level. Tuesday will have sun with flurries, -5 °C in the morning then a high of -2 °C, gusting 35 km/h winds, and 1900m freezing level. Wednesday will be sun and cloud, -7 to 0 °C, light winds, and 2200m freezing level.

Terrain and Travel Advice

  • Cornices become weak with daytime heating.
  • In areas where deep persistent slabs may exist, avoid shallow or variable depth snowpacks and unsupported terrain features.
  • Avoid exposure to slopes that have cornices overhead.

Regions covered