Debris Flow
A fast-moving slurry of mud, rock and debris, usually on a slope soaked by heavy rain or stripped by a fire. Every one the National Weather Service has filed, by year and by state, with the deadliest and costliest.
The deadliest and costliest on the map
The deadliest and costliest debris flow episodes on record.
- Tornadoes
- Tropical storms and surge
- Floods
- Wind
- Hail
- Winter weather
- Heat and drought
- Cold
- Fire, smoke and dust
- Marine and coastal
- Other
The record
- Events
- 2,545
- Deaths
- 153
- Injuries
- 253
- Damage
- $1.4 billion
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
Every year
Deaths each year
The deadliest
Deaths from this kind of event within each episode.
- Debris Flow in Washington, March 22, 2014A relatively dry October 2013 through early February 2014 period with precipitation running around only 50 percent of normal turned unusually wet one week into February and continued through March.
- Winter Storm and Debris Flows in California, January 9, 2018A powerful winter storm impacted Southwestern California in early January. This storm generated heavy rainfall with totals ranging from 1-4 inches across the coasts and valleys with up to 7 inches over some foothill and mountain areas.
- Flash Flooding and Debris Flow in California, December 25, 2003Steady light to moderate rain began falling over the burned areas of the San Bernardino Mountains on 0600 PST 12/24/03. Approximately 24 hours later, mud, rock, and debris flows were being reported along highways and roads leading into the mountain resort communities.
- Tornado and Tropical Storm in North Carolina, September 25 to 29, 2024Tropical Cyclone Helene began organizing over the western Caribbean on the 23rd and 24th of September before rapidly intensifying as it moved north through the eastern Gulf of Mexico on the 25th and 26th.
- Flash Flooding and Winter Storm in California, January 7 to 11, 2005A powerful Pacific storm brought heavy rain, snow, flash flooding, high winds and landslides to Central and Southern California. During the 5 day event, rainfall totals ranged from 3 to 10 inches over coastal areas with up to 32 inches in the mountains.
- Blizzard and Winter Storm in Alaska, November 20 to 21, 2023A hurricane-force 964 mb low lifted out of the North Pacific and into the Gulf of Alaska through the early morning hours of November 20, 2023.
- Debris Flow and Flooding in North Carolina, September 16 to 17, 2004In response to persistent moderate to heavy rainfall associated with the remnants of Hurricane Ivan, severe flooding developed across the mountains for the second time in 9 days.
- Debris Flow in Washington, January 19, 1997A mudslide kills a family of four while they were sleeping in their home. The house, on Bainbridge Island, slid down a hill into Puget Sound. 20 other homes in the vicinity were evacuated.
- Debris Flow and Damaging Winds in New Mexico, July 8, 2025The monsoon high was centered over the Arizona and New Mexico border July 8th. Daytime heating combined with rich Gulf moisture along the east slopes of the Sacramento Mountains resulted in the development of thunderstorms over the west end of the South Fork burn scar during the…
- Flash Flood and Debris Flow in Alaska, August 18 to 19, 2015A strong front moved through the Panhandle on the morning of Tuesday August 18th. This system had abundant amount of moisture associated with the cold front as the system originated from the North Pacific and was able to tap into tropical moisture.
- Debris Flow in Colorado, May 25, 2014During the peak of snowmelt on the Grand Mesa was a period of heavy rainfall which may have combined to precipitate a massive landslide on the north side of the Grand Mesa.
- Debris Flows and Flooding in Alaska, December 1 to 5, 2020A large plume of concentrated moisture or Atmospheric River (AR) with an associated low-pressure system moved across the Pacific Ocean and transported tropical moisture from the southwest which impacted Southeast Alaska (SEAK) from December 1st through December 2nd.
- Debris Flow in North Carolina, May 30, 2018Heavy rainfall on the afternoon of May 30th caused a debris flow into a home that later contributed to a fatal gas explosion that killed two people.
- Flash Flooding and Debris Flows in Puerto Rico, October 25 to 28, 2007A 1006 millibar low pressure area centered southwest of the Mona passage and its associated bands of clouds, showers and thunderstorms affected Puerto Rico during the period from October 25-29.
- Debris Flow and Flooding in California, December 27, 2022A strong upper low pressure system moved through California on December 27. This system had abundant moisture associated with it as it pulled up a deep fetch of moisture of tropical origin.
- Debris Flow and Flooding in California, February 17 to 22, 2024A winter storm mid-February brought several days of continued heavy snow, rain, and gusty winds. Periods of chain controls were observed in the mountains with local reports of flooding and minor wind damage.
- Tornadoes and Flash Flooding in North Carolina, August 17 to 18, 2021Tropical Storm Fred made landfall in the Florida Panhandle on the 16th and lifted steadily north through Georgia and into the southern Appalachians during the 16th and throughout the 17th.
- Debris Flows and Flooding in Washington, December 2 to 5, 2007Record flooding occurred on the Chehalis, Skokomish, and Elwha Rivers. In addition to the record flooding, major flooding occurred on the Bogachiel River.
- Debris Flow in California, April 1 to 15, 2006Persistent heavy rainfall caused a massive number of landslides across the Sonoma and Marin County valleys area during the first half of April. About $20 million of damage was done to agriculture, with over $9 million spent in road repair damage in Sonoma County alone.
- Debris Flow in Tennessee, February 21, 2019A wet February caused soils to be near saturation. Abundant Gulf moisture associated with approaching frontal boundaries and a southwesterly 500 MB flow produced additional heavy rainfall over the Cumberland Plateau.
- Storm Surge and Flash Flooding in California, September 9 to 12, 2022Tropical Cyclone Kay formed on September 4th, 2022 and made its closest approach to Southern California on the 9th and 10th, with the center of Kay coming within 120 miles of San Diego.
- Debris Flows in Alaska, August 25, 2024A low-pressure system moved out of the North Pacific Ocean into the Gulf of Alaska and quickly intensified into a 995 MB gale-force storm on the Sunday morning of August 25th, 2024.
- Debris Flows and Flooding in North Carolina, May 5 to 7, 2013A strong upper low slowly lifted northeast across the southern Appalachian Mountains over the 3 day period.
- Debris Flow and Flooding in New Hampshire, October 29 to 30, 2012On Monday, October 29th, Hurricane Sandy (and its remnants) tracked northwest from well off the North Carolina coast to southeastern Pennsylvania, making landfall near the southern tip of New Jersey.
- Flash Flooding and Debris Flow in North Carolina, May 18 to 19, 2018Wait for it.
The costliest
Damage from this kind of event within each episode, in the dollars of its year.
- Winter Storm and Debris Flows in California, January 9, 2018
- Debris Flows and Hail in Colorado, July 29, 2021
- Debris Flow in Washington, March 22, 2014
- Storm Surge and Debris Flows in California, December 28 to 31, 2005
- Debris Flow and Damaging Winds in New Mexico, July 8, 2025
- Debris Flow in California, October 3, 2007
- Debris Flow in California, April 1 to 15, 2006
- Debris Flow in California, June 1, 2005
- Flash Flooding and Debris Flows in Colorado, July 31, 2021
- Debris Flow in Washington, October 10 to 11, 2009
- Debris Flows and Flooding in Alaska, December 1 to 5, 2020
- Debris Flows and Flooding in Washington, January 7 to 10, 2009
- Debris Flow in Tennessee, February 20 to 24, 2019
- Flash Flooding and Debris Flows in California, December 19 to 25, 2010
- Debris Flow in California, April 4 to 12, 2006
- Debris Flow in Utah, October 8, 2011
- Debris Flow in California, April 2 to 16, 2006
- Debris Flow in California, April 6 to 20, 2006
- Flash Flooding and Debris Flows in New Mexico, June 29 to 30, 2024
- Debris Flow and Flood in North Carolina, September 16 to 17, 2004
- Debris Flow and Flood in North Carolina, September 7 to 8, 2004
- Debris Flow in California, May 19 to 21, 2017
- Debris Flow in Tennessee, February 21, 2019
- Tornadoes and Debris Flows in California, January 6 to 12, 2017
- Debris Flow in California, April 1 to 25, 2006
By state
| State or waters | Events | Deaths | Injuries | Damage |
|---|---|---|---|---|
| California | 767 | 53 | 188 | $903 million |
| Puerto Rico | 629 | 3 | 4 | $9.1 million |
| Colorado | 303 | 7 | 14 | $161 million |
| Washington | 188 | 48 | 15 | $113 million |
| Utah | 90 | 0 | 5 | $13 million |
| Oregon | 79 | 2 | 8 | $2.8 million |
| Idaho | 76 | 0 | 0 | $8.8 million |
| North Carolina | 64 | 22 | 11 | $39 million |
| Kentucky | 60 | 0 | 0 | $77,000 |
| Nevada | 44 | 0 | 0 | $154,000 |
| Arizona | 32 | 0 | 0 | $175,000 |
| Virginia | 29 | 0 | 0 | $896,000 |
| Hawaii | 25 | 0 | 0 | $3.9 million |
| Alaska | 21 | 12 | 4 | $37 million |
| New Mexico | 21 | 3 | 2 | $61 million |
| West Virginia | 21 | 1 | 0 | $1.2 million |
| Montana | 18 | 0 | 2 | $137,000 |
| New York | 10 | 0 | 0 | $515,000 |
| Tennessee | 9 | 1 | 0 | $26 million |
| Pennsylvania | 8 | 0 | 0 | $80,000 |
| Wyoming | 7 | 0 | 0 | $1.2 million |
| Alabama | 6 | 0 | 0 | $129,000 |
| Georgia | 6 | 0 | 0 | $310,000 |
| New Hampshire | 3 | 1 | 0 | |
| Guam | 3 | 0 | 0 | $216,000 |
| American Samoa | 3 | 0 | 0 | $75,000 |
| Texas | 3 | 0 | 0 | |
| Arkansas | 3 | 0 | 0 | $75,000 |
| Massachusetts | 3 | 0 | 0 | $50,000 |
| Ohio | 3 | 0 | 0 | $2,000 |
| Maine | 2 | 0 | 0 | $920,000 |
| Illinois | 2 | 0 | 0 | $50,000 |
| Minnesota | 1 | 0 | 0 | |
| South Carolina | 1 | 0 | 0 | |
| Florida | 1 | 0 | 0 | $75,000 |
| Vermont | 1 | 0 | 0 | |
| Mississippi | 1 | 0 | 0 | $25,000 |
| Wisconsin | 1 | 0 | 0 | $1,000 |
| U.S. Virgin Islands | 1 | 0 | 0 | $1,000 |
Every kind of event
- Thunderstorm Wind
- Hail
- Flash Flood
- High Wind
- Winter Storm
- Drought
- Winter Weather
- Tornado
- Heavy Snow
- Flood
- Marine Thunderstorm Wind
- Heat
- Heavy Rain
- Strong Wind
- Excessive Heat
- Extreme Cold/Wind Chill
- Cold/Wind Chill
- Lightning
- Dense Fog
- Blizzard
- Frost/Freeze
- Ice Storm
- High Surf
- Funnel Cloud
- Wildfire
- Tropical Storm
- Waterspout
- Coastal Flood
- Lake-Effect Snow
- Debris Flow
- Hurricane (Typhoon)
- Dust Storm
- Rip Current
- Storm Surge/Tide
- Marine High Wind
- Sleet
- Avalanche
- Marine Hail
- Astronomical Low Tide
- Marine Tropical Storm
- Tropical Depression
- Freezing Fog
- Lakeshore Flood
- Dust Devil
- Marine Strong Wind
- Dense Smoke
- Marine Hurricane/Typhoon
- Volcanic Ashfall
- Seiche
- Sneakerwave
- Volcanic Ash
- Tsunami
- Marine Tropical Depression
- Marine Dense Fog
- Northern Lights
- Marine Lightning
- Hurricane
Sources
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24.