Wildfires, such as the Missionary Ridge fire that burned for more than a month in 2002 near Durango, Colorado (Fig. 1), and their aftermath can cause subsequent property and environmental damage. Many areas denuded by the fire are now susceptible to rapid erosion during heavy precipitation with resulting debris flows, or mudslides.
U.S Highway 85 and ND Highway 22, along with numerous county roads, buildings, pipelines, and power lines, have been constructed over existing landslides in the Little Missouri Badlands of western North Dakota. Since 1980, the repair and rerouting of damaged sections of highways in this area have cost taxpayers more than $5 million (Fig 1). In one instance, a one-mile segment of U.S. Highway 85 was rerouted from one area of landslides into another. Better understanding of landslide hazards is needed in this area.
Landslides affect all 50 states and U.S. territories, though mountainous regions such as the Pacific Coast range, the Rockies, the Appalachians, Alaska, and Hawaii bear the most severe risk. The U.S. Geological Survey estimates that each year in the United States, landslides cause the deaths of 25 to 50 people and losses of at least $1 billion.