Bollettino valanghe

Coquihalla

Feb 15 – 16, 2023Avalanche Canada
Vedi sulla mappa
Archiviato · scaduto 4 years ago

Pericolo valanghe

Fri
Sat
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
Apri la mappa completa

In sintesi

Avalanches are possible in wind-loaded areas at treeline and above. Winds have changed directions and built wind slabs on all aspects. Carefully evaluate wind loading in terrain and investigate the bond of wind slabs to the crust below them before committing to a slope.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2.5

    Northerly winds are distributing 20 cm of storm snow into lees on south slopes. Watch for areas that have been reverse-loaded and cross-loaded at higher elevations.

    On Wednesday, winds change to southwesterly and will begin building fresh wind slabs on north and east slopes. Look for fresh windslab development as you travel into higher elevations. Wind slabs may be sitting on a crust making them especially reactive to ridder triggering.

    During periods of direct sun watch for slab properties increasing in surface snow. Minimize exposure to steep sun-exposed slopes, especially when solar radiation is strong.

Confidence

Moderate

Avalanche Summary

Poor visibility for the last few days kept operators from seeing avalanche activity at higher elevations.

On Saturday two notable wind slab avalanches were reported. First, a machine accidental, size 2-2.5, wind slab avalanche on a northeast aspect at 1900 m. See this great MIN report for photos. Second was a natural, size 2, wind slab avalanche that initiated in steep northeast facing terrain. The avalanche ran off some cliffs and triggered a second slab below them.

Please continue to post your reports and photos to the Mountain Information Network.

Snowpack Summary

20 cm of storm snow is being redistributed by variable winds. New snow overlies 50 cm of wind-affected snow in exposed areas. In sheltered areas, the upper snowpack remains unconsolidated.

A melt-freeze crust formed in mid-January is now buried up to 100 cm deep. At the moment this layer appears to be gaining strength though in isolated areas small facets are still found above the crust. The snow below this layer is consolidating nicely. Buried 120-150 cm is a crust, formed near the end of December.

Snowpack depths are below seasonal averages. Total amounts range from 150 to 200 cm at treeline, but decrease significantly below 1500 m.

Weather Summary

Tuesday Night

Clear with cloudy periods. Winds northwest switching to west 25 km/h gusting 40 km/h. Treeline temperatures -8 °C. Freezing levels drop to valley bottom. 

Wednesday 

Mix of sun and cloud. Winds southwest 20 km/h gusting 40 km/h. Treeline temperatures -6 °C. Freezing levels of 700 m. 

Thursday

Cloudy with sunny periods. Winds southwest 20 km/h gusting 60 km/h. Treeline temperatures -5 °C and freezing levels of 1000 m. 

Friday

Cloudy with isolated flurries, 2-3 cm accumulation. Winds west 20 km/h gusting 40 km/h. Treeline temperatures -6 °C and freezing levels of 800 m. 

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Recent wind has varied in direction so watch for wind slabs on all aspects.
  • Approach lee and cross-loaded slopes with caution.
  • Avoid freshly wind loaded features, especially near ridge crests, roll-overs and in steep terrain.
  • Be alert to conditions that change with elevation and sun exposure.

Regioni coperte