Most large slab avalanches run on slopes between 25 and 45 degrees. This range includes the average angle of coire backwalls and approach slopes to crags. Smooth ground such as rock slab is predisposed to full depth avalanches. Rough ground such as large boulders will tend to anchor base layers in position, making avalanches less likely. Once these boulders are covered, however, surface avalanche activity is unhindered.
Convex slopes are generally more hazardous than uniform or concave slopes.
The point of maximum convexity is a frequent site of tension fractures, with the release of slab avalanches. Ridges or buttresses are better choices than open slopes and gullies when avalanche conditions prevail. The crests of mountain ridges are usually protected from avalanches, while in climbing situations, rock belays on ribs and buttresses can often provide security. Lee slopes should be avoided after storms or heavy drifting. Their location will obviously vary according to wind direction, but will include the sheltered side of ridges and plateau rims.