Influence of hydrometeorological controls on debris flows near Chilliwack, British Columbia

This study aims to identify hydrometeorological variables near Chilliwack, BC which have initiated past debris flows in order to gain insight about conditions that could inform emergency planning and adaptation in future. A database of storms between 1980 and 2007 and their hydrometeorological characteristics including storm total rainfall and duration, intense rainfall total and duration, and 1 to 4 week cumulative antecedent rainfall were compiled. Stepwise logistic regression was used to determine a model which isolated intense rainfall total and occurrence of storms during the rain-on-snow season as the most significant variable distinguishing between debris flow and non-debris flow storms. However, the low predictive power of this analysis suggests that other characteristics, such as land-use, sediment supply, and snow melt may play a large role in debris flow initiation in this region.