Date issued

May 2, 2018 - 4:00 PM

Valid until

until further notice

Prepared by

ian jackson

This is the last scheduled avalanche bulletin for the season. Above average snowpack at high elevations means we should have an extended spring ski season! Check out the Mountain Conditions Report weekly regional summaries for up to date conditions.

Spring Season Conditions

Avalanche Problem 1: Loose Wet

What Elevation?
Which Slopes?
Chances of Avalanches?
Expected Size?

Warm temperatures or rain will rapidly increase the likelihood of loose wet avalanches at all elevations. Pay close attention to the integrity of surface crusts and avoid traveling in avalanche terrain once the crusts have broken down.

Travel and Terrain Advice
  • Watch for clues, like sluffing off of cliffs, that the snowpack is warming up.
  • Avoid sun exposed slopes when the solar radiation is strong, especially if snow is moist or wet.

Avalanche Problem 2: Wet Slabs

What Elevation?
Which Slopes?
Chances of Avalanches?
Expected Size?

New snow, intense heating or large triggers could cause wet slabs in steep terrain, possibly stepping down to deeper weak layers in the snow pack. Avoid exposure to steep slopes if the snow is becoming moist or wet.

Travel and Terrain Advice
  • Travel early before the heat of the day melts surface crusts, and avoid big slopes in the afternoon.

Avalanche Problem 3: Cornices

What Elevation?
Which Slopes?
Chances of Avalanches?
Expected Size?

Cornice failures are occurring on a regular basis with warm temperatures, new loading or intense solar inputs. In some places these large triggers have also caused failures on the deeper weak layers in the snow pack pulling out larger slabs.

Travel and Terrain Advice
  • Cornices become weak with daytime heating, so travel early on exposed slopes.
  • Minimize exposure to overhead hazard from cornices.

Avalanche Summary

In general, avalanche hazard will be greatest during hot sunny days or warm rain. This has the potential to trigger smaller loose wet avalanches and larger wet slab avalanches on the basal weak layer. For current avalanche activity and observations, check out the Mountain Conditions Report

Snowpack Summary

Isothermal snow exists at lower elevations. Crusts formed during clear cool nights will break down quickly with solar inputs and daytime warming. Expect moist surface snow to mountain top in the afternoon with the exception of high elevation north slopes. Buried weak layers persist at treeline and above and will become reactive as temperatures warm

Weather Forecast

Some helpful weather links:

Remote weather stations in Banff, Yoho & Kootenay - Real time, raw, actual weather data.

Avalanche Canada Mountain Weather Forecast - Good for getting an overview of the major weather systems.

SpotWx - Good for a localized forecast

Environment Canada Yoho forecast - Simplified valley bottom forecast for Lake Louise area.

Danger Ratings Explained

1 - Low

Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

Natural and human-triggered avalanches unlikely.

Small avalanches in isolated areas or extreme terrain.

2 - Moderate

Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern.

Natural avalanches unlikely; human-triggered avalanches possible.

Small avalanches in specific areas; or large avalanches in isolated areas.

3 - Considerable

Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential.

Natural avalanches possible; human-triggered avalanches likely.

Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas.

4 - High

Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.

Natural avalanches likely; human-triggered avalanches very likely.

Large avalanches in many areas; or very large avalanches in specific areas.

5 - Extreme

Avoid all avalanche terrain.

Natural and human-triggered avalanches certain.

Large to very large avalanches in many areas.

Avalanche Forecasts in your Inbox

Avalanche Canada has switched to an RSS feed for its daily forecasts. This is a much more flexible method that allows automatic delivery to your email inbox, or to an RSS reader of your choice.

What are RSS feeds?

RSS (Really Simple Syndication) is a popular standardized file format allowing up-to-date delivery of web-based content. RSS feeds enable you to receive content updates from websites, delivered to your email through an RSS aggregator (such as blogtrottr.com) or viewed through applications called RSS readers (such as feedly.com).

Set up an RSS feed for your email:

Select a RSS aggregator

  1. Avalanche Bulletin - Banff, Yoho, and Kootenay National Parks URL: http://www.avalanche.ca/api/forecasts/banff-yoho-kootenay.rss
  2. Copy the url and paste it into the appropriate field of your RSS aggregator.
  3. Fill in your email address.
  4. Voila! Watch the Avalanche Canada forecast roll into your inbox.

Forecast Disclaimer

Avalanche Canada's Public Avalanche Bulletin, and other information and services provided by Avalanche Canada, are intended for personal and recreational purposes only.

**THIS INFORMATION IS PROVIDED "AS IS" AND IN NO EVENT SHALL THE PROVIDERS BE LIABLE FOR ANY DAMAGES, INCLUDING, WITHOUT LIMITATION, DAMAGES RESULTING FROM DISCOMFORT, INJURY, OR DEATH, CLAIMS BY THIRD PARTIES OR FOR OTHER SIMILAR COSTS, OR ANY SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, ARISING OUT OF THE USE OF THE INFORMATION.**

The user acknowledges that it is impossible to accurately predict natural events such as avalanches in every instance, and uses the data in this bulletin with this always foremost in mind. The accuracy or reliability of the data is not guaranteed or warranted in any way and the Providers disclaim liability of any kind whatsoever, including, without limitation, liability for quality, performance, merchantability and fitness for a particular purpose arising out of the use, or inability to use the data.