Banff Yoho & Kootenay National Park Avalanche Forecast

Issued: Apr 14th, 2021 4:00PM

Wed Apr 14th Current Conditions
Alpine Below Threshold Treeline Below Threshold Below Treeline Below Threshold
Thu Apr 15th 2 Day Outlook
Alpine Below Threshold Treeline Below Threshold Below Treeline Below Threshold
Fri Apr 16th 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 Wet, Cornices and Persistent Slabs.

The first real test of the snowpack will occur over the next few days. Temperatures will increase more each day, and the window between Low and High avalanche danger will shorten. Expect a good freeze Thursday AM.

Summary

Weather Forecast

A good freeze expected for Thursday AM with freezing levels rising to 2600m during the day and lots of punch from the sun. There will be light E/NE winds. Friday freezing levels will be 2900m, and Saturday 3000m which signals the hottest period yet this spring and the first real test of the snowpack.

Snowpack Summary

15 to 30 cm of settled recent snow at treeline. Crusts up to around 2000m on all aspects and to ridge crest on solar aspects. Several persistent layers exist in the mid to lower snowpack that might be a concern in thin areas with significant warming or with larger triggers like cornices which are prevalent in the alpine.

Avalanche Summary

One size 3 deep persistent slab triggered by cornice failure Tuesday at 10 am on Mt. Stanley. There was also a couple of deeper slab avalanches noted, both East aspects in the alpine. One was just left of the Victoria/Collier Col, and the other off of Mt. Niblock. They are suspect to have release in the past 24 hours and were both size 2.5.

Confidence

Problems

Loose Wet

An icon showing Loose Wet

Likelihood

Very Likely - Likely

Expected Size

1 - 2

With intense solar inputs expected and lots of loose snow on solar aspects, we expect many loose wet avalanches over the next few days. Keep an eye on any sun exposed terrain above you and be off steep solar terrain before these start.

  • Watch for clues, like sluffing off of cliffs, that the snowpack is warming up.
  • Daytime warming will weaken surface layers, plan your day around being back to the trailhead early.

Aspects:

East, South East, South, South West, West.

Elevations:

All elevations.

Cornices

An icon showing Cornices

Likelihood

Likely

Expected Size

1.5 - 3

Cornices are huge and are failing consistently, sometimes triggering deeper layers in the snowpack. With the intense solar input forecasted, they may start to fail early in the day.

  • Give cornices a wide berth when traveling on ridges.
  • Pay attention to overhead hazards like cornices which could easily trigger persistent slabs.

Aspects:

North, North East, East, South East, North West.

Elevations:

Alpine.

Persistent Slabs

An icon showing Persistent Slabs

Likelihood

Possible

Expected Size

2 - 3

Warming temperatures may cause this problem to start showing up again. Significant solar warming, high alpine thin snowpack areas, or places where a large cornice might have enough punch to trigger the deeper layers are the main areas of concern.

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

Aspects:

All aspects.

Elevations:

Alpine.

Valid until: Apr 15th, 2021 4:00PM

Forecast Trend

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