COMPARING LANDSLIDES AND DEBRIS FLOWS ASSOCIATED WITH WINTER STORMS OF 2016-2017 WITH THOSE IN 2005-2006 AND 1996-1997 ON THE KLAMATH NATIONAL FOREST, CENTRAL KLAMATH MOUNTAINS, CA

Winter storms of January 2017 triggered many landslides in the Klamath Mountains of NW California, resulting in widespread damage to roads & infrastructure. A partial landslide inventory on the Klamath National Forest in 2017 has identified more than three million dollars of damage to date. A previous storm in January of 2006 caused more infrastructure damage ($5 million). An even larger storm in January of 1997 caused $27 million dollars in damage, and resulted in significantly more landslides than the two more recent storms. The large differences in landslide response between these storms could be due to a variety of factors, such as local variations in storm intensities, wildfire burn severity, land management practices, antecedent moisture conditions, or snow melt. Little is known about variations in rainfall intensity during intense winter storms in the area prior to 2006. Since that time, an array of tipping bucket rain gages has been installed, and Remote Automated Weather Stations (RAWS) have been established that allow a better assessment of precipitation patterns for the most recent event in January of 2017. This information will allow us to better isolate the effects of forest management practices and wildfire from those of rainfall variations, and help facilitate evaluation of effectiveness of the repair of legacy sites which are landslides and other sediment producing sites associated with land management. Furthermore, it will help evaluate modeled predictions of post-fire debris flows and the effectiveness of post-fire road repairs intended to withstand debris flows and flooding.