What is a debris flow?
Debris flows are fast-moving landslides that are particularly dangerous to life and property because they move quickly, destroy objects in their paths, and often strike without warning. They occur in a wide variety of environments throughout the world, including all 50 states and U.S. Territories. Debris flows generally occur during periods of intense rainfall or rapid snowmelt and usually start on hillsides or mountains. Debris flows can travel at speeds up to and exceeding 35 mph and can carry large items such as boulders, trees, and cars. If a debris flows enters a steep stream channel, they can travel for several miles, impacting areas unaware of the hazard. Areas recently burned by a forest fire are especially susceptible to debris flows, including the areas downslope and outside of the burned area. Debris flows are a type of landslide and are sometimes referred to as mudslides, mudflows, lahars, or debris avalanche.
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New Landslide Guidebook for Puerto Rico Residents
A new landslide guidebook released February 5 is now available for Puerto Rico residents to learn more about the landslide hazards that can impact the island.
Landslide Risks Highlighted in New Online Tool
The U.S. Geological Survey today unveiled a new web-based interactive map that marks an important step toward mapping areas that could be at higher risk for future landslides. In collaboration with state geological surveys and other federal agencies, USGS has compiled much of the existing landslide data into a searchable, web-based interactive map called the U.S. Landslide Inventory Map.
Predicting Postfire Debris Flows Saves Lives
When wildfires spread and scorch the earth, people like Penny Luehring have to act fast. Secondary impacts such as debris flows can be devastating to nearby communities.
PubTalk 10/2018 — Post-fire debris flow early warning
Title: Post-Fire Debris-Flow Early Warning: The case for forecast-based warning systems
- Post-fire debris flows can initiate after only a few minutes of intense rain, and during the first storm following wildfire.
- Early warning systems must provide sufficient time to make informed decisions and take reasonable preventative action.
- If you're
Montecito after debris flow
The Dec. 4, 2017 Thomas fire, Southern California's largest wildfire on record, burned more than 280,000 acres across Ventura and Santa Barbara counties for nearly a month.
Post-wildfire debris flow: 2016 Fish Fire, Las Lomas Canyon
The June 2016 Fish Fire burned over 12 km^2 in Los Angeles County, California. After the fire, the USGS installed an automated rain-triggered camera to monitor post-wildfire flooding and debris flow in a small canyon above the Las Lomas debris basin in Duarte. This video shows the peak flow triggered by an intense rainstorm on January 20, 2017.
Predicting Postfire Debris Flows Saves Lives
Predicting Postfire Debris Flows Saves Lives
Post-wildfire Flood and Debris Flow: 2014 Silverado Fire
In 2014, the Silverado Fire burned approximately 4 km^2 in Orange County, California. After the fire, the USGS installed an automated rain-triggered camera to monitor post-wildfire flooding and debris flow at the outlet of a small 0.6 km^2 basin within the burn area. This video shows the initial surge and peak flow triggered by an intense rainstorm on July 19, 2015. The
Volcano Web Shorts 2: Debris Flows
Debris flows are hazardous flows of rock, sediment and water that surge down mountain slopes and into adjacent valleys. Hydrologist Richard Iverson describes the nature of debris-flow research and explains how debris flow experiments are conducted at the USGS Debris Flow Flume, west of Eugene, Oregon. Spectacular debris flow footage, recorded by Franck Lavigne of the
LS Post Fire Debris Flow
Downstream impacts of a post-fire debris-flow in Mullally Canyon on February 6, 2010, near La Canada-Flintridge, California. Debris flow was generated during a burst of high-intensity rainfall over the area burned by the September 2009 Station Fire.
Landslide monitoring equipment with debris flow
Debris-flow monitoring station at the Arroyo Seco monitoring site established after the 2009 Station Fire, CA.
USGS and California Wildfires: Post Fire Debris Flow (part 2)
Jim Bowers, USGS, California Hydrologic Monitoring Program Chief talks about the potential for debris flows in central Orange County, Modjeska Canyon, as a result of the 2007 fires.
USGS and California Wildfires: Post Fire Debris Flow (part 1)
Jim Bowers, USGS, California Hydrologic Monitoring Program Chief, talks about an historic streamflow site that was buried by debris flows as a result of the 2003 fires.
Post-fire Debris Flow
Debris Flow in Cable Canyon following the 2003 Old Fire in the San Bernardino Mountains, California.
Comet Falls with the 2001 Van Trump Creek debris flow, which origin...
Comet Falls with the 2001 Van Trump Creek debris flow, which originated at Kautz Glacier on Mount Rainier, Washington.