Avalanche Awareness

Presented byCanada West Mountain School

Avalanche HazardTriangle

People or property

Avala

nche

Terr

ain

AvalancheHazard!

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Unstable snow

Loose Snow Avalanches

Photo: Mark Austin

Photo: Jasper National Park

Failure of slab through additional weight

Failure in tensile

strength

Local Shearfailure

Wind

Failure in tensile

strengthShear failure

Increased loadon lee slope

Constant sluffs;Large slabs uncommon

Frequent small avalanches;infrequent large slabs

Largest slabs;Frequent avalanches

60-90 degrees

45-60 degrees

25-45 degrees

Dry slabs are uncommon;

Wet avalanches canoccur occasionally

10-25 degrees

90

60

45

25

25-45 includes a lot of common terrain!

Start Zone: Critical Angles

Angles are only relevant to terrain in starting zones!

Avalanche “Crown” approx. 2m in depth. Size 3 avalanche, 28 degree slope at fracture lineDec 27, 2008

Snowpack StructureUnderstand the snow pack if you are in Avi terrain

• Weather creates the snowpack

know the weather history

• Terrain effects modify the snowpack

pay attention to changes in terrain

• The snowpack will change over time

constantly re-asses snow conditions

• Have a visual picture of the snowpack

Information gathering for backcountry winter travellers

Where do we get our info??

• Public Avalanche Bulletins• Weather offices, websites, etc• Highways departments• Parks offices• Local guides• Ski patrols• Local outdoor stores• Clubs and members• Information from prior trips• Online forums• Friends, people on the trail

Avalanche Bulletins

• Canadian Avalanche Center Bulletin

• Whistler-Blackcomb Avalanche Advisory

• North Shore Avalanche Advisory

• US Avalanche resources (avalanche.org)

• European Bulletins

Weather information

• Environment Canada Weather –Public Text forecast–Satellite imagery

• Whistler-Blackcomb Alpine• Mount Seymour Alpine• Western Washington Univ.• Mountain Weather Services• Ski Resort Forecasts (snow-forecast.com)

Highways Departments

• Highways Webcams (and others)

• DriveBC.com

Local Guides

• Mountain Conditions Report (MCR)

• ACMG

• Canada West Mountain School

Other resources

• National Parks offices• Outdoor stores• Online forums

– Telemarktips.com– CAA Forum

• Clubs and members• Information from prior trips• Friends, people on the trail

Anniversary Glacier Avalanche and historical run-outs – Jan. 2008

Flute Bowl, Whistler Mountain – May 2008