Avalanche Forecast

Lizard Range and Flathead

Date issued

Dec 6, 2017 - 4:26 PM

Valid until

Dec 7, 2017 - 2:00 PM

Prepared by

cgarritty

A rapid shift to warm, sunny conditions will increase the range of avalanche problems as well as their potential for reactivity.

Regular season
Wednesday - December 6, 2017
Alpine

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.

Treeline

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.

Below Treeline

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.

Thursday - December 7, 2017
Alpine

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.

Treeline

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.

Below Treeline

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.

Friday - December 8, 2017
Alpine

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.

Treeline

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.

Below Treeline

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.

Avalanche Problem 1: Wind Slabs

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

A recent wind shift from southwest to north means that fresh wind slabs are likely to now exist on a wide range of aspects at higher elevations. Be especially cautious of reverse loaded or cross-loaded slopes that see sun exposure on Thursday.

Travel and Terrain Advice
  • Be careful with wind loaded areas, especially near ridge crests and roll-overs.
  • Use ridges or ribs to avoid pockets of wind loaded snow.

Avalanche Problem 2: Loose Wet

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

Warm, sun-exposed slopes could produce wet loose avalanches either naturally or with rider triggers on Thursday, especially in steeper terrain. This problem will likely be limited to areas above the valley cloud.

Travel and Terrain Advice
  • Minimize exposure to steep, sun exposed slopes when the solar radiation is strong.
  • Be cautious of sluffing in steep terrain, particularly where the debris flows into terrain traps.

Avalanche Summary

Reports from Tuesday included several observations of wind slabs releasing to Size 2 in the Fernie area. These were mainly triggered with explosives but one Size 1.5 slab did release with skier traffic. Looking forward, forecast sunshine and warm temperatures may have the greatest destabilizing effect where more recent reverse loading and crossloading has occurred at higher elevations.

Please submit your observations to the Mountain Information Network (MIN).

Snowpack Summary

Recent shifting winds have been redistributing loose snow at higher elevations, crossloading and forming wind slabs on a wide range of aspects at treeline and above. Below the surface, 40-60 cm of accumulated storm snow now sits above the crust that formed a week ago. The buried crust is supportive and approximately 30 cm thick. It extends from 1600 m to mountain top elevations on all aspects. The bond of our recent storm snow to this crust is expected to be strengthening and it has produced hard, resistant results in recent snowpack tests. Below this interface, the snowpack is moist to ground. The average snowpack depth at treeline is 60-80 cm while a deeper snowpack exists in the alpine.

Weather Forecast

Thursday: A mix of sun and cloud with thicker valley cloud due to an alpine temperature inversion. Light west winds. Freezing level to 3300 metres with alpine temperatures of +4. Cooler at lower elevations

Friday: Sunny at highest elevations with valley cloud due to lingering temperature inversion. Light west winds. Freezing level to about 3200 metres with alpine temperatures of +2. Cooler at lower elevations.

Saturday: Mainly sunny at highest elevations with continued valley cloud. Light southwest winds. Freezing level to 3300 metres with alpine temperatures of +3. Cooler at lower elevations.

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. Lizard Range and Flathead URL: http://www.avalanche.ca/api/forecasts/lizard-range.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.