Abstract Research in recently burned mountainous watersheds in California, Colorado, and Utah shows that most postfire debris flows are initiated by runoff and erosion and grow in size through erosion and scour in channels. Most commonly, postfire debris flows occur within two years after a fire. This paper describes a field trip to three such occurrences in the southeastern Sierra Nevada as well as debris flows in the arid Inyo Mountains. On 12 July 2008, tropical moisture moved across the American Southwest and stalled against the eastern Sierra. Local convective cells simultaneously produced brief periods of intense rainfall on steep-sloped, burned watersheds near the towns of Lake Isabella and Independence, about 155 km to the north. Both communities sustained significant damage and infrastructure disruption. On 10 August 2010, intense rain fell on the Haiwee Creek drainage that was burned in 2008, producing a debris flow that swept a semi tractor trailer off of Highway 395, caused overnight traffic delays, and damaged infrastructure.