Avalog Join
Archived

Avalanche Forecast

Mar 11th, 2023–Mar 12th, 2023
Alpine
2: Moderate
The avalanche danger rating in the alpine will be moderate
Treeline
2: Moderate
The avalanche danger rating at treeline will be moderate
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate
Alpine
4: High
The avalanche danger rating in the alpine will be high
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
3: Considerable
The avalanche danger rating below treeline will be considerable
Alpine
3: Considerable
The avalanche danger rating in the alpine will be considerable
Treeline
3: Considerable
The avalanche danger rating at treeline will be considerable
Below Treeline
2: Moderate
The avalanche danger rating below treeline will be moderate

Regions: Little Yoho.

While these deeper snowpack zones seem to be a bit better than the rest of the forecasting region, concern remains for the persistent weak layers to be human triggered from shallow or rocky areas, or for them to be triggered by large loads, such as a falling cornice or moving avalanche.

Moderate terrain choices with limited overhead hazard continue to be the best way to manage the uncertainty in the snowpack.

Watch for hazard ratings to rise Monday with a warm, wet Pacific flow incoming.

Confidence

Moderate

Avalanche Summary

Not much avalanche activity has been observed in this area during the past week, however in the thinner snowpack areas of the BYK region, we continue to see significant avalanches on the different persistent layers.

Snowpack Summary

A sun crust is present on steep solar slopes at treeline and below while 10-30 cm of soft snow can be found on northerly aspects. The various January persistent weak layer interfaces (sun crusts, facets, and surface hoar) are now down 60-120 cm. The weaker Nov. 16 basal facet layer is down 110-170 cm and continues to produce whumpfing and moderate to hard sudden collapse results in snowpack tests.

Weather Summary

Mainly cloudy skies with trace amounts of accumulation will persist overnight Saturday through Sunday with west-southwest winds peaking near 30km/h and alpine temperatures warming a bit to between -10 and -15C.

Sunday evening snowfall will increase to bring 5cm overnight as winds increase to 40km/h and shift southwest and a strong Pacific flow of moisture begins.

10-20cm of snow is expected Monday with freezing levels approaching 2000m and winds increasing to beyond 50km/h.

Terrain and Travel Advice

  • Avalanche hazard may have improved, but be mindful that deep instabilities are still present.
  • Uncertainty is best managed through conservative terrain choices at this time.

Avalanche Problems

Deep Persistent Slabs

Weaker facets and depth hoar remain at the bottom of the snowpack and inspire little confidence. Be especially cautious in thin snowpack, or rocky areas, where triggering is more likely. Large loads such as cornice failures or smaller avalanches may act as a trigger for this layer so careful consideration of the terrain you travel beneath is wise.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible

Expected Size: 1.5 - 3

Persistent Slabs

Three persistent weak layers formed in January are down 60-110 cm. Buried sun crusts found on steep solar slopes present the greatest concern for triggering on these interfaces however weak facets and isolated surface hoar can be found on the same interfaces on shaded aspects.

Aspects: All aspects.

Elevations: All elevations.

Likelihood: Possible

Expected Size: 1.5 - 2.5