Aerial view of debris-flow deposition resulting in widespread destruction on the Caraballeda fan of the Quebrada San Julián. Avulsion of the main channel (left side of photo) resulted in deposits up to 6-m in thickness and totaling about 1.8 million cubic meters of bouldery debris. Secondary new flood channels are visible through center of fan to the lower right of photo (Photo by Lawson Smith, Waterways Experiment Station, US Army Corps of Engineers).
Heavy rainfall from the storm of December 14-16, 1999 triggered thousands of landslides on steep slopes of the Sierra de Avila north of Caracas, Venezuela. In addition to landslides, heavy rainfall caused flooding and massive debris flows that damaged coastal communities in the State of Vargas along the Caribbean Sea. Examination of the rainfall pattern obtained from the GOES-8 satellite showed that the pattern of damage was generally consistent with the area of heaviest rainfall. Field observations of the severely affected drainage basins and historical records indicate that previous flooding and massive debris-flow events of similar magnitude to that of December 1999 have occurred throughout this region. The volume of debris-flow deposits and the large boulders that the flows transported qualifies the 1999 event amongst the largest historical rainfall-induced debris flows documented worldwide. FOR MORE INFORMATION PLEASE SEE: "Debris-flow and flooding hazards associated with the December 1999 storm in coastal Venezuela and strategies for mitigation", USGS Open-file report online: http://pubs.usgs.gov/of/2001/ofr-01-0144/