Debris Flow Traversal Areas are headwater channels with a modeled probability of runout by a debris flow that continues to a fish-bearing stream. Riparian zones along the traversal area, or corridor, are sources of wood carried by debris flows to fish streams. The traversal areas are ranked based on the predicted probability, or likelihood, of debris flows along the channel. Probability is expressed in terms of the proportion of the total debris flow track length included within any watershed population of debris flow traversal areas associated with the likelihood of their occurrence. The highest 20% of the likelihood of debris flow traversal associated with 20% of the total track length in the population is ranked: zero to 20%; the next 20% is ranked as 21% to 40%, and so on.

Debris Flow Traversal Areas are headwater channels with a modeled probability of runout by a debris flow that continues to a fish-bearing stream. Riparian zones along the traversal area, or corridor, are sources of wood carried by debris flows to fish streams. The traversal areas are ranked based on the predicted probability, or likelihood, of debris flows along the channel. Probability is expressed in terms of the proportion of the total debris flow track length included within any watershed population of debris flow traversal areas associated with the likelihood of their occurrence. The highest 20% of the likelihood of debris flow traversal associated with 20% of the total track length in the population is ranked: zero to 20%; the next 20% is ranked as 21% to 40%, and so on.