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Hazard Assessment - Topographic Exposure

Topographic Exposure Show Larger Image

How would you assess topographic hazard?

Constrictions increase topographic hazard, while shelter reduces topographic hazard. If the area is neither sheltered nor exposed, the topographic hazard is moderate.

In complex terrain, it is necessary to estimate the dominant direction(s) of damaging winds. Storm direction can be estimated on a site-by-site basis by mapping the directions of windthrown trees.

The diagnostic question for topographic exposure is 'are winds normal for the area, or do they vary due to a terrain obstacle or constriction?'

Note the dominant damaging wind direction(s); may be more than one dominant direction. Wind funnels within valleys and through passes. Note that shoulders where valleys change direction are high hazard.

 

 
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