Bollettino valanghe

Crowsnest North

Mar 1 – 2, 2023Avalanche Canada
Vedi sulla mappa
Archiviato · scaduto 4 years ago

Pericolo valanghe

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

In sintesi

Greatest hazard exists at treeline elevations, with wind loading lower on slopes than you might expect. Wind slabs may not bond well with the hard surfaces below. Expect reactivity and give them a wide berth.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    Southwesterly winds have formed wind slabs on north and east facing slopes. Alpine slopes are mostly stripped back to hard surfaces, but isolated pockets of wind loading may remain triggerable to humans. Greatest likelihood of wind slabs is at treeline elevations.

    Pay particular attention to wind loading mid to low on slopes at treeline elevations, and be wary of cross-loaded features.

    A melt freeze crust from mid-January has shown some reactivity, small wind slabs may step down to this layer resulting in a bigger avalanche.

Confidence

Moderate

Avalanche Summary

Over the last 3 days natural wind slabs have been reported to size 2.5, out of north facing alpine features. Reports suggest winds have mostly stripped the alpine, with isolated features holding wind loading now.

On Saturday, wind slab avalanches were reported to size 1.5, triggered by sleds.

Please post your field observations and photos on the Mountain Information Network.

Snowpack Summary

Around 15 cm of new snow has fallen in the last 3 days. At higher elevations this sits over extremely wind affected surfaces including large sastrugi. Many alpine areas may not hold new snow and instead be stripped back to hard surfaces.

A melt-freeze crust with facets above, sits 50 to 100 cm deep. This crust could be a good sliding surface for avalanche activity but has shown limited reactivity so far. We are monitoring this layer going forward as it may become a persistent problem.

The mid to lower snowpack is considered well bonded at this point. Currently we are not seeing the same basal weak layers and reactivity that many of the neighboring regions are experiencing this season.

Weather Summary

Tuesday Night

Mainly cloudy with flurries. Light to moderate southwest winds. Freezing levels at valley bottom.

Wednesday

Cloudy with sunny periods and isolated flurries. Moderate westerly winds. Alpine high of -6 °C. Freezing levels 500 m.

Thursday

Cloudy with light snowfall 5-10 cm. Strong southwest winds. Alpine highs of -7 °C, freezing levels around 1000 m.

Friday

Mix of sun and cloud with moderate westerly winds. Freezing level around 1000 m. Flurries deliver light snowfall.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
  • Although their spatial distribution is isolated, wind slabs are reactive.

Regioni coperte