Slope length contributes to the force an avalanche can generate. Avalanche fatalities due to suffocation have, however, been reported on very short slopes. Slope shape and roughness contribute to the frictional forces that hold the snowpack in place. Concave and irregular slopes tend to be more stable than smooth, convex slopes. Boulders, shrubs, and trees add to slope roughness and therefore provide more stability than grass or smooth rock.
Avalanches do, however, occur occasionally in heavily timbered areas.
Slope elevation and aspect dictate the depth, temperature, an moisture characteristics of the snowpack that develop due to the interaction of the contributing weather factors. Weather variables, especially snowfall, affect the timing and duration of hazardous snow avalanche conditions. Snowfall amount, rate of accumulation, moisture content, and snow crystal types all contribute to the magnitude of unstable conditions. Wind is another critical weather variable capable of depositing large amount of dense snow into starting zones. Strong winds are capable of creating an unstable load rapidly even when little or no new snow has fallen.