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2018 Southern California mudflows

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2018 Southern California debris flows
Homes and streets of a neighborhood affected by the Santa Barbara County mudslides
DateJanuary 9, 2018 (2018-01-09)
LocationSouthern California, United States
CauseSoil saturation from heavy rainfall, and deforestation due to recent wildfires
Non-fatal injuries163
Property damage>$207 million (2018 USD)[2][3]
  • 65 residences destroyed, 462 residences damaged, 8 commercial buildings destroyed, 20 commercial buildings damaged

A series of mudflows occurred in Southern California in early January 2018, particularly affecting areas northwest of Montecito in Santa Barbara County. The incident was responsible for 23 deaths,[4] although the body of one of the victims has never been found.[5] Approximately 163 people were hospitalized with various injuries, including four in critical condition.[6] The disaster occurred one month after a series of major wildfires. The conflagrations devastated steep slopes, which caused loss of vegetation and destabilization of the soil and greatly facilitated subsequent mudflows. The mudflows caused at least $177 million (2018 USD) in property damage,[2] and cost at least $7 million in emergency responses[2] and another $43 million (2018 USD) to clean up.[3]


The 2017 California wildfire season was at the time the most destructive in California's history, with approximately 9,133 wildfires that burned over 1.3 million acres (5,300 km2) and killed 46 people.[7] At the beginning of December, the Santa Ana winds fanned wildfires across southern California, which were fueled by a lack of rainfall during what is normally the region's rainy season.[8] The December fires burned 307,953 acres (124,624 ha) of which 281,893 acres (114,078 ha) were burned during the Thomas Fire, the largest fire in the state's history at the time.[4][5] The Thomas Fire, which devastated parts of Santa Barbara and Ventura counties, burned large amounts of vegetation whose roots had helped stabilize topsoil in hillsides and other vulnerable areas.[9] After burning for more than a month, the fire was declared fully contained on January 12, 2018.[10]

A strong low-pressure system and cold front developed off the coast of California on January 5, 2018.[11] The system moved onto the mainland on January 8, bringing heavy rain to Southern California and prompting mandatory evacuations in parts of Los Angeles, Santa Barbara, and Ventura counties, over potential mudslides in areas affected by wildfires.[12] The storm intensified on the following day, with at least four inches (100 mm) of rain falling over the two-day period, before ending on January 9, causing several major mudflows.[13][14]


Santa Barbara County[edit]

San Ysidro Ck. after debris flow
Butterfly Beach debris

Early on the morning of January 9, mudflows struck Montecito, which had been affected by the Thomas Fire, and other areas of Santa Barbara County.[15] An estimated 0.5 inches (13 mm) of rain fell within a five-minute period at approximately 3:30 a.m., causing mud and boulders from the Santa Ynez Mountains to flow down creeks and valleys into Montecito.[16] The debris flows were up to 15 feet (5 m) in height of mud, boulders and tree branches, moving at estimated speeds of up to 20 miles per hour (30 km/h) into the lower areas of Montecito.[17][18] Over 20,000 people lost power, and a 30-mile (50 km) section of U.S. Route 101 (US 101) from Santa Barbara to Ventura was shut down as sections filled with two feet (60 cm) of mud and debris, some of which also reached beaches 2.25 miles (3.6 km) from the mountains.[19][20][21] Following the closure, access to Santa Barbara from the Los Angeles area was limited to a 260-mile (420 km) detour around the Los Padres National Forest or through the use of private ferries to Ventura.[22] On January 11, Amtrak train service was restored to Santa Barbara and US 101 was partially reopened as far west as Carpinteria.[23] The highway was fully reopened on January 21, after Caltrans crews cleared 12 feet (3.7 m) of mud from the roadway.[24][25]

Approximately 21,000 residents of Santa Barbara and Ventura counties in high elevation zones affected by the Thomas Fire were evacuated,[26] but low-lying areas were outside of the mandatory evacuation area.[27][28] Warning messages sent by the National Weather Service and the county government arrived too late to prompt Montecito residents to seek safe areas.[29] Many residents in the mandatory evacuation zone, and most residents in the voluntary evacuation area, ignored warnings and stayed in their homes, probably a result of "evacuation fatigue" left over from the recent wildfires.[30] The mandatory evacuation zone was expanded to cover a majority of Montecito's estimated 10,000 residents two days later (January 11) due to disruptions in electricity, gas, water, sewage and Internet, and due to emergency road works and ongoing search and rescue operations.[31]

The mudflows caused 23 confirmed deaths, mostly in the Montecito area. One body, that of two-year-old Lydia Sutthithepa, was never recovered.[32] Over 150 people were hospitalized with various injuries, including four in critical condition.[6] The mudflows destroyed over 100 homes and damaged an additional 300.[33] Writer T.C. Boyle, whose home was proximate to both the fire and mudslides, documented the collective trauma in The New Yorker magazine.[34]

Cleanup efforts began a week after the initial mudflows, with debris being sent to the Ventura County Fairgrounds for sorting and the Calabasas Landfill for disposal.[35][36]

Los Angeles County[edit]

Parts of Burbank and Sun Valley, previously affected by the La Tuna Fire in 2017, received four inches (100 mm) of rain and were evacuated ahead of potential mudslides. A debris flow into a residential area of Sun Valley damaged 40 to 45 homes and carried a vehicle that struck a natural gas pipeline, which began to leak.[37] Mandatory evacuations were ordered for nearby areas of the San Fernando Valley affected by the Creek Fire before the storm, but no major damage was reported.[38][39]

Orange and Riverside counties[edit]

Heavy rain in Corona, affected by the Canyon Fire, covered streets with mud and flooded into several homes, but no major damage was reported.[40]


More than 1,250 firefighters from California and other states, along with the California Conservation Corps and California National Guard, were dispatched to Santa Barbara County for search and rescue operations.[27][17] Numerous civilian volunteers also came out in force to help with the clean up effort. The Federal Emergency Management Agency announced that emergency assistance funds related to the wildfires would be extended to cover damage from the mudflows.[41] The U.S. Army Corps of Engineers also worked quickly in awarding contracts that involved removal of debris from various water basins and channels.[citation needed]

Approximately 300 residents of the Romero Canyon neighborhood near Montecito were rescued via a helicopter airlift after roads were blocked by debris.[42]

See also[edit]


  1. ^ Martinez, Alys (January 9, 2019). "One year later, symbol of hope found in Montecito mud". KEYT 3. Archived from the original on May 6, 2019. Retrieved May 6, 2019.
  2. ^ a b c "The Economic Impacts of the Montecito Mudslides: A Preliminary Assessment" (PDF). Robert D. Niehaus, Inc. March 2018. Archived from the original (PDF) on 26 May 2018. Retrieved 26 May 2018.
  3. ^ a b Giana Magnoli (27 February 2018). "County Estimates $46 Million Cost for Thomas Fire, Montecito Debris Flow Response, Repairs". Noozhawk. Retrieved 26 May 2018.
  4. ^ a b Sanders, Linley (December 22, 2017). "California's Thomas Fire Breaks Record As Largest Wildfire in State History". Newsweek. Retrieved January 10, 2018.
  5. ^ a b Flores, Oscar (December 4, 2017). "Thomas Fire burns 281,893 acres, nears full containment". KEYT 3. Retrieved January 10, 2018.
  6. ^ a b "California: Thirteen dead in Montecito rains and mudslides". BBC News. January 10, 2018. Retrieved January 11, 2018.
  7. ^ Tierney, Lauren (January 4, 2018). "The grim scope of 2017's California wildfire season is now clear. The danger's not over". The Washington Post. Retrieved January 10, 2018.
  8. ^ Holthaus, Eric (December 14, 2017). "The Thomas Fire Could Become the Largest Wildfire in California History". Pacific Standard. Retrieved January 10, 2018.
  9. ^ Serna, Joseph; Panzar, Javier (January 8, 2018). "Rains finally arrive, bringing new danger in California's vast fire zones". Los Angeles Times. Retrieved January 10, 2018.
  10. ^ Livingston, Michael; Grad, Shelby (January 12, 2018). "Thomas fire, California's largest on record, finally 100% contained". Los Angeles Times. Retrieved January 12, 2018.
  11. ^ Lindsey, John (January 6, 2018). "SLO County is expected to get heavy rain Monday and Tuesday — here's why". The Tribune. San Luis Obispo. Retrieved January 10, 2018.
  12. ^ von Quednow, Cindy; Pascucci, Christina; Lyster, Lauren; Myers, Erin; Friel, Courtney (January 8, 2018). "1st Major Storm of the Year Brings Rain to SoCal, Triggers Evacuations Amid Concerns of Mudslides in Burn Areas". KTLA 5 News. Retrieved January 11, 2018.
  13. ^ "The rain is done in Southern California. How much did we get?". Los Angeles Daily News. January 10, 2018. Retrieved January 11, 2018.
  14. ^ "Monday's Southern California storm is nothing compared to what we're getting Tuesday". Los Angeles Daily News. January 8, 2018. Retrieved January 11, 2018.
  15. ^ Mejia, Brittny; Hamilton, Matt; Etehad, Melissa; Tchekmedyian, Alene (January 11, 2018). "Up to 43 people still missing in Montecito; dead include four children". Los Angeles Times. Retrieved January 11, 2018.
  16. ^ Schleuss, Jon; Smith, Doug; Boxall, Bettina (January 12, 2018). "Tracking a path of destruction from Montecito's mountains to the ocean". Los Angeles Times. Retrieved January 12, 2018.
  17. ^ a b Doubuzinskis, Alex (January 12, 2018). "'Window closing' for California mudslide searchers as death toll rises to 18". Reuters. Retrieved January 12, 2018.
  18. ^ Hamilton, Matt; Serna, Joseph (January 12, 2018). "Montecito braced for fire, but mud was a more stealthy, deadly threat". Los Angeles Times. Retrieved January 12, 2018.
  19. ^ Google Maps (Map). Retrieved April 18, 2018.
  20. ^ Bertola, Alexa (January 10, 2018). "Highway 101 closure adds hours to drivers' commutes". KSBY 6. Archived from the original on January 11, 2018. Retrieved January 12, 2018.
  21. ^ Queally, James; Serna, Joseph; Livingston, Michael; Vives, Ruben (January 9, 2018). "At least 13 dead as heavy rains trigger flooding, mudflows and freeway closures across Southern California". Los Angeles Times. Retrieved January 11, 2018.
  22. ^ Boone, Alastair (January 11, 2018). "With the Highway Blocked, California Commuters Take to the Sea". CityLab. Retrieved January 12, 2018.
  23. ^ Forgione, Mary (January 11, 2018). "Train service to Santa Barbara restored; 101 Freeway open as far as Carpinteria". Los Angeles Times. Retrieved January 11, 2018.
  24. ^ Dolan, Jack (January 21, 2018). "Highway 101 in Santa Barbara County reopens, nearly two weeks after a massive mudslide". Los Angeles Times. Retrieved January 21, 2018.
  25. ^ Wenzke, Marissa (January 21, 2018). "101 Freeway in Santa Barbara County Reopens After Being Blocked Following Deadly Mudslides". KTLA. Retrieved January 21, 2018.
  26. ^ Raphelson, Samantha (January 12, 2018). "Southern California Hillsides Remain Vulnerable After Deadly Mudslides". NPR. Retrieved January 12, 2018.
  27. ^ a b Livingston, Michael; Branson-Potts, Hailey; Etehad, Melissa; Serna, Joseph (January 10, 2018). "Deadly flooding on Santa Barbara coast as fire turns to mud". Los Angeles Times. Retrieved January 11, 2018.
  28. ^ Serna, Joseph; Livingston, Michael (January 9, 2018). "Montecito neighborhood ripped by mudslides was not under mandatory evacuation order". Los Angeles Times. Retrieved January 11, 2018.
  29. ^ Serna, Joseph; Branson-Potts, Hailey; Vives, Ruben; Nelson, Laura J. (January 11, 2018). "Urgent alerts about deadly mudslides came too late for Montecito victims". Los Angeles Times. Retrieved January 12, 2018.
  30. ^ Biasotti, Tony; Ufberg, Max; Wilson, Scott (January 11, 2018). "'Evacuation fatigue' caused some to ignore peril of mudslides". The Washington Post. Retrieved January 11, 2018.
  31. ^ Gutman, Matt; Hutchinson, Bill (January 12, 2018). "10,000 evacuated after mudslides in Montecito, rescuers scramble to find missing". ABC News. Retrieved January 12, 2018.
  32. ^ Hahn, Jason (July 23, 2021). "Teen's Body Found 3 Years After Death in Calif. Mudslide, Mom Says He'll Be Buried Next to Dad". People. Retrieved March 14, 2022.
  33. ^ Queally, James; Etehad, Melissa; Mejia, Brittny (January 10, 2018). "Death toll rises to 17 in Montecito; 100 homes destroyed by mudslides". Los Angeles Times. Retrieved January 11, 2018.
  34. ^ After the mudslides, an absence in Montecito, The New Yorker, T.C. Boyle, January 22, 2018.
  35. ^ Kohli, Sonali; Hamilton, Matt; Serna, Joseph (January 16, 2018). "Rain expected this week may hamper Montecito and 101 cleanup efforts". Los Angeles Times. Retrieved January 16, 2018.
  36. ^ Lehr, Tracy (22 July 2018). "Crews work to repave Ventura Fairgrounds parking lot following disaster mud removal". KEYT-TV. Archived from the original on 23 July 2018. Retrieved 22 July 2018.
  37. ^ "With rain gone, some Burbank evacuations are lifted, but La Tuna Canyon Road evacuations remain". Los Angeles Daily News. January 11, 2018. Retrieved January 11, 2018.
  38. ^ Gazzar, Brenda (January 8, 2018). "Fearing mudslides, mandatory evacuations ordered in some fire burn areas, with more anticipated". Los Angeles Daily News. Retrieved January 12, 2018.
  39. ^ "Evacuations ordered in SoCal burn areas amid flood warnings". ABC 7 News. January 10, 2018. Retrieved January 12, 2018.
  40. ^ Valenzuela, Beatriz E. (January 10, 2018). "Mud several inches deep cakes Corona streets in Canyon fire burn area". The Press-Enterprise. Retrieved January 11, 2018.
  41. ^ Yadegari, Brandon; Yamamura, Jean (January 11, 2018). "More Rescuers Arrive to Search Montecito". Santa Barbara Independent. Retrieved January 11, 2018.
  42. ^ Tchekmedyian, Alene (January 9, 2018). "About 300 people still stuck in Romero Canyon; rescue operations will resume at daybreak". Los Angeles Times. Retrieved January 11, 2018.

Further reading[edit]

  • Keller, Edward; Adamaitis, Chandler; Alessio, Paul; Goto, Erica; Gray, Summer (2020), "Montecito debris flows of 9 January 2018: Physical processes and social implications", From the Islands to the Mountains: A 2020 View of Geologic Excursions in Southern California, Geological Society of America, pp. 95–114, doi:10.1130/2020.0059(03), ISBN 978-0-8137-0059-5