42
Basic Avalanche Awareness: An introduction to snow safety in Svalbard Holt Hancock 07/02/2017 Cryoslope Svalbard photo
Basic Avalanche Awareness: An introduction to snow safety in Svalbard
Holt Hancock 07/02/2017 Cryoslope Svalbard photo
Introduction • Avalanches occur throughout
svalbard
• Unique avalanche conditions and problems associated with Svalbard’s climate and setting
• Recreationalists typically
cause avalanches that affect their group – This is preventable!
Eckerstorfer and Christiansen image
Introduction
If you don’t know, don’t go
Think terrain, not snow
Human factors
3 Axioms / Things to remember:
If you don’t know, don’t go
• Types of avalanches in Svalbard
• Weather warning signs
• Snowpack warning signs
What is an avalanche?
A mass of snow sliding, tumbling, or flowing down an inclined surface
What is an avalanche?
A mass of snow sliding, tumbling, or flowing down an inclined surface
Svalbard (Snow) Avalanches
4 Types • Slab • Cornice fall • Slushflows
(slush avalanches)
• Loose snow
Slab avalanches
– Cohesive layer of snow that slides on underlying layers
– Triggered by the victim or a member of their party
SLF photo
Most recreational avalanche accidents involve slab avalanches
Slab avalanches
Slab: wind drifted snow or new storm snow
Weak layer: facets (sugar snow)
Bed surface: ice layer or hard old snow
Slab avalanches Lia, 2010 Max Eckerstorfer photo
Crown (Slab)
Weak layer
Bed surface
Slab avalanches
Starting zone / release area
Track / Path
Runout / deposition zone / debris
Slab avalanches
Cryoslope Svalbard photo
Slab avalanches Erik Næss photo
Slab avalanches
Cryoslope Svalbard photo
Cornice fall avalanches First, what is a cornice?
Cryoslope Svalbard photo
Cornice fall avalanches
Not always this obvious where the cornice starts!!
Cryoslope Svalbard photo
Cornice fall avalanches
Cryoslope Svalbard photo
• Very common avalanche type in Svalbard
• Slab avalanche often releases due to impact of falling cornice
• Difficult to forecast timing of cornice failure
• End of snow season • Warm temperatures • During storms?
Cornice fall avalanches
Cryoslope Svalbard photo
Slushflows
Cryoslope Svalbard photo
Slushflows
• Slush avalanches
• Associated with heavy rain / snow melt
• Snowpack becomes saturated
• Occur in different terrain than other avalanches
Svalbardposten photo from January 30th, 2012
Loose snow avalanches
Cryoslope Svalbard photo
Avalanche Triangle
Terrain
Is the weather contributing to increased avalanche danger?
Terrain
Warning Signs: Weather
Recent heavy snowfall (>15 cms) Erik Næss photo
Warning Signs: Weather
Strong winds; especially in combination with loose snow
Cryoslope Svalbard photo
Warning Signs: Weather
Rapid warming and rain
Cryoslope Svalbard photos
Is the snowpack unstable?
Terrain
Warning Signs: Snowpack Recent avalanche activity
Cryoslope Svalbard photos
Warning Signs: Snowpack Shooting cracks and ‘‘whumpfing’’
If you don’t know, don’t go
• What can we do to know? – Check the weather and avalanche forecast
• Varsom.no
– Look for signs of recent avalanche activity and unstable snow
– Ask!
• Think terrain, not snow
Think terrain, not snow If snow is the problem, terrain is the answer
Terrain
What is avalanche terrain? Release areas • Avalanches typically
release on slopes between 30 and 45 degrees
• ‘‘steep slopes’’
Cryoslope Svalbard photo
A brief note on slushflows:
• Release from lower angle terrain (typically 5 – 30 degrees)
• Watch for water pooling in the snowpack
Erik Hestnes figure
What is avalanche terrain?
Runout Zones • During periods of
elevated avalanche danger, valleys are not necessarily safe!
• It is possible to trigger avalanches from below
Cryoslope Svalbard photo
Terrain Traps Especially dangerous avalanche terrain
Think terrain, not snow
• Learn to identify slope angles – Avoid steep slopes
• Be aware of your surroundings – Runout zones – Terrain traps
Human factors
Terrain
What were they thinking?!
What was I thinking?!
People
The human factor
Common human factors / errors • Time constraints (weekend warrior) • Familiarity • Group dynamics • Expert halo • Blue sky syndrome
Most avalanches involving people are triggered by their own actions!
The human factor
• Safe travel protocols – Basic avalanche gear – One at a time in avalanche terrain
• Communicate within your group – Speak up!!
• Have a plan…but be flexible!
How can we reduce our risks?
Trip Planning
Consider:
• Is the weather contributing to increased avalanche danger?
• Is the snowpack unstable?
• Will I be traveling in avalanche terrain?
• How are human factors influencing my (our) assessment of the avalanche hazard?
Again, remember:
If you don’t know, don’t go
Think terrain, not snow
Human factors
Questions?
Have a fun (and safe) winter and spring!
