Banff Yoho & Kootenay National Park Avalanche Forecast

Issued: Apr 18th, 2021 4:00PM

Sun Apr 18th Current Conditions
Alpine Below Threshold Treeline Below Threshold Below Treeline Below Threshold
Mon Apr 19th 2 Day Outlook
Alpine Below Threshold Treeline Below Threshold Below Treeline Below Threshold
Tue Apr 20th 3 Day Outlook
Alpine Below Threshold Treeline Below Threshold Below Treeline Below Threshold

The alpine rating is below threshold, the treeline rating is below threshold, and the below treeline rating is below threshold. Known problems include Loose Dry, Loose Wet and Persistent Slabs.

A quick return to winter on Sunday has made new snow surface instabilities the main concern for the next couple of days.

Summary

Weather Forecast

A cold front dropping through Alberta has brought 10-15 cm with moderate NE winds as of Sunday afternoon. Temperatures are expected to drop as low as -15C in the alpine and just below 0C at valley bottom overnight. An unstable atmosphere seems likely Monday that should result in spotty clouds while freezing levels approach 2000m in the afternoon.

Snowpack Summary

Up to 15cm of new snow Sunday tapers with elevation and buries crusts found on solar aspects and up to 2200m on shaded aspects. Persistent layers in the mid and lower snowpack were re-activated in a few instances during the heating over the last week producing avalanches with cornice failures and explosives.

Avalanche Summary

On Friday and Saturday explosive control on the 93 S and in Yoho produced good results up to size 3 with small slabs at treeline gouging into deeper layers at lower elevations and running full path. Widespread natural loose wet avalanche activity up to size 2 was also observed at all elevations. Cooling Sunday has brought natural activity to a halt

Confidence

Problems

Loose Dry

An icon showing Loose Dry

Likelihood

Likely

Expected Size

1 - 1.5

New snow amounts will vary across the region and with elevation. Sluffing is likely in steep terrain over firm underlying surfaces and crusts. Use caution in gully features where these events could gather mass.

Aspects:

All aspects.

Elevations:

Alpine, Treeline.

Loose Wet

An icon showing Loose Wet

Likelihood

Possible

Expected Size

1 - 1.5

Heating on Monday will depend on cloud cover, but as the winds abate in the afternoon, it will not take much sun to develop point releases in the new snow, especially around exposed rock. These may run far on the well developed crusts.

  • Use extra caution on solar slopes or if the snow is moist or wet.

Aspects:

South, South West, West.

Elevations:

Alpine, Treeline.

Persistent Slabs

An icon showing Persistent Slabs

Likelihood

Unlikely

Expected Size

2 - 3.5

Cooler temperatures may decrease the likelihood of deeper layers in the mid to lower snowpack being triggered. If there is a poor freeze or one of the many large cornices fails, larger avalanches on these layers are still a possibility.

  • Pay attention to overhead hazards like cornices which could trigger persistent slabs.
  • Pockets of persistent slabs linger on alpine lee features.

Aspects:

North, North East, North West.

Elevations:

Alpine.

Valid until: Apr 19th, 2021 4:00PM

Forecast Trend

The latest forecast danger ratings, broken down to elevation. See how an elevation is trending.