The Deadly Montecito Post-Fire Debris Flow of January 9, 2018 and the Successes and Challenges of Post-Fire Debris-Flow Prediction and Early Warning
Abstract
The Thomas Fire erupted on December 4, 2017 and burned 281,893 acres within Ventura and Santa Barbara Counties in southern California - becoming California's largest wildfire on record. The timing of this fire was especially unfortunate given it occurred within southern California's winter rainy season, thus the burn scar immediately posed threats of post-fire debris flows whenever impacted by intense rainfall. Numerous communities lie just beneath the burn scar, including the community of Montecito located along coastal Santa Barbara County. The U.S. Geological Survey (USGS) Landslide Hazards Program immediately began their post-fire debris-flow hazard assessment. Once intense rainfall was forecasted, the National Weather Service (NWS) used rainfall rate thresholds determined by the USGS as conducive to producing post-fire debris flows to alert community officials and the public in advance. The system was tested when a strong Pacific storm system moved through the area in morning hours of January 9th, producing very heavy rainfall in a short period of time over the Thomas burn scar just above Montecito. This torrential rainfall produced one of the more catastrophic debris-flow events on record in California, resulting in 21 fatalities and 2 residents still missing and presumed deceased, a total of 128 single family residences destroyed and 307 damaged, and 6 commercial properties destroyed and 17 damaged. Although so many lives were lost, emergency response agencies - who had additional and pre-positioned resources in place due to the advanced hazard information provided by the NWS and the USGS - were able to conduct 1000 rescues in the first 24 hours. Officials estimate the number of fatalities could have been doubled had it not been for these resources in place for immediate response. This presentation will describe the post-fire debris-flow hazard assessment and early warning system, summarize the extreme nature of this event, and describe the successes and challenges associated with predicting and responding to this event. In addition, we will discuss the assessment and mitigation of debris-flow hazards through the remainder of the winter and spring of 2018, and plans for forthcoming season.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMNH34C..01J
- Keywords:
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- 1616 Climate variability;
- GLOBAL CHANGEDE: 1920 Emerging informatics technologies;
- INFORMATICSDE: 4313 Extreme events;
- NATURAL HAZARDSDE: 4341 Early warning systems;
- NATURAL HAZARDS