Avalanche Forecast

South Coast Inland

Date issued

Feb 15, 2018 - 4:46 PM

Valid until

Feb 16, 2018 - 2:00 PM

Prepared by

shorton

Heavy snowfall in the southern part of the region on Friday will make conditions more dangerous than in the north.

Regular season
Thursday - February 15, 2018
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.

Friday - February 16, 2018
Alpine

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.

Treeline

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.

Below 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.

Saturday - February 17, 2018
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

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.

Avalanche Problem 1: Wind Slabs

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

The Coquihalla may get 20 cm of new snow on Friday, which will result in touchy slabs in wind-affected terrain. Northern parts of the region have older wind slabs on a wide range of aspects.

Travel and Terrain Advice
  • Approach steep lee and cross-loaded slopes with caution.
  • Be careful with wind loaded pockets, especially near ridge crests and roll-overs.
  • Minimize exposure during periods of heavy loading from new snow and wind.

Avalanche Problem 2: Cornices

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

Large, looming cornices have formed along ridgelines. They need to be given an extra wide berth from above and below. A large cornice collapse in the north of the region may have the ability to trigger a deeply buried weak layer.

Travel and Terrain Advice
  • Firm cornices can pull back into flat terrain at ridgetop if they fail.
  • Falling cornices may trigger large avalanches on slopes below.

Avalanche Summary

No new avalanches were reported on Thursday.

On Wednesday, several size 2 wind slabs (40 cm thick) were triggered with explosives on south-facing slopes in the Duffey area. Wind slab activity has been reported in the northern part of the region over the past week, including some small (size 1) skier triggered slabs and some larger (size 2-3) naturally triggered slabs on a range of aspects in alpine terrain (some of which were triggered by cornices).

Expect the incoming snow to form fresh slabs, particularly in wind-affected terrain.

Snowpack Summary

Southern parts of the region are expecting heavy snowfall on Friday and Saturday, likely forming fresh storm slabs as snow accumulates. Northern parts of the region are getting lighter amounts, so fresh slab development will primarily occur in wind-affected terrain.

A few interfaces buried 10-20 cm below the most recent snow could potentially support wide propagations in the fresh storm/wind slabs. These include scoured crusty surfaces on south-facing alpine slopes, a melt-freeze crust up to about 1900 m, and old wind slabs on a range of aspects at high elevations.

The mid-January crust is now buried beneath 80-150 cm of settled snow and may remain sensitive to large triggers - especially in thinner snowpack areas in the north part of the region. Large, looming cornices exist, they are fragile, and they demand respect. Cornice falls are very effective triggers for avalanches on the slopes below them.

Weather Forecast

FRIDAY: Flurries easing throughout the day with 10-20 cm of new snow in the south and trace amounts in the north, moderate west wind, alpine high temperatures around -6 C in the north and -3 C in the south.

SATURDAY: Moderate snowfall with 10 cm throughout the day in the north and 30 cm in the south, strong southwest wind, alpine high temperatures around -6 C in the north and -2 C in the south.

SUNDAY: Clearing and cooling with strong northeast wind and alpine high temperatures around -18 C in the north and -8 in the south.

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. South Coast Inland URL: http://www.avalanche.ca/api/forecasts/south-coast-inland.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.