3 x 3 avalanche hazard scale by Werner Munter 3 x 3 Avalanche Assessment Process
Created by Werner Munter
3x3 Table and Reduction Method are to be used together to obtain acceptable avalanche risk
Note: This system is not designed nor intended for use in the United States. It is presented as an example of the excellant work being done in Europe on avalanche hazard analysis. For further information on this method get the book.
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3Factors/3Filters
Snowpack/Weather
Terrain
Human Factor

Regional
TourPlanning
Avalanche Report, Weather forcast, Info. from locals, etc. Use 1:25,000 Map, Guide books, Photos, Own knowledge Who's coming with? Skill level? Equipment? Who's responsible? Researchable information
Local
Visible area and route selection
General snow conditions, Wind direction and loading, New snow amounts, Oddities, Visibility, Temperature Check info you've previously received, I.e. Relief, slope angle, steepness, ski tracks, etc.., Are there existing ski tracks-how many and when made? Who's in my group? Equipment and Transceivers with? Time plan for tour? Itinerary left with someone? Observations before setting out
Zonal
Exact location of questionable slope
Check new snow amounts, Visibility, Solar radiation, Assess possible slab potential, What's keeping the snow together? What's above and below me?, Steepest part of slope, Near the ridge? Any wind pockets? Tiredness, Discipline, Technique, Distance between each other, how wide of a track? Think! Go or not to Go

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Reduction Method
Acceptable Risk =
Danger Potential
<=1
Red. Factor x Red. Factor

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Avalanche
Report
Danger
Potential
1 2
2 4
3 8
4 16
5 32
Reduction Factors:

First Class Steepest Slope Angle 35-39 Degrees RF2
Steepest Slope Angle 30-34 Degrees RF4
Second Class Northern Sector Slope (NW-N-NE) RF2
Northern half Sector Slope (WNW-N-ESE) RF3
Avoiding Named Avalanche slope sectors RF4
Third Class Constantly skied slope RF2
Large groups with distance between each RF2
Small group (2-4 persons) RF2
Small group with distance between each RF3

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Do not use this system without more knowledge of avalanches

Example:
You're skiing with one other person in a new area with no visible tracks
Avalanche Report is 4 Danger Potential = 16
Steepest Slope angle is 38 degrees RF 2
Slope is in Northern Section RF 2
Small group (2-4 persons) RF 2
Reduction Method example computed
Acceptable Risk =
16
= 2
2 x 2 x 2=8
The result is greater than one so No Go!

Ideally the Acceptable Risk Factor will be less than 1.
Equal to 1 is questionable!

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