Flash Flood in the United States

How dangerous are Flash Flood events in the U.S.?

Human impact is a defining part of this hazard's NOAA record. Across 45,915 events, the database lists 1,089 fatalities and 314 injuries. PlainHazard places hazard types with at least 100 recorded fatalities in its very-high human-toll band. That is a descriptive grouping of this 2015-2025 catalog, not an official NOAA risk grade and not a statement about the severity of every individual event.

This hazard is recorded far more often than it proves fatal. Among the 44 hazard types with at least 100 recorded events it ranks #3 by frequency but only #18 by fatalities per event, at 23.7 deaths per 1,000 recorded events. Recorded damage averages $1.8M per event, so its cumulative toll is driven mainly by how routinely it occurs rather than by the severity of any one event.

The year-to-year record shows real volatility around a high baseline. The peak year on record was 2025, logging 5,393 events and $1.3B in property damage in a single calendar year. The most recent year in the dataset is 2025 with 5,393 events recorded. Across the full 11-year window, annual event counts reflect seasonal climate cycles (ENSO phases, active vs. quiet severe-weather years) and long-term shifts tied to a warming climate both help explain the swings.

Frequency and financial loss occupy a similar place in the NOAA catalog for this hazard. Its #3 event-count rank sits within four positions of its #1 combined-damage rank; the listed losses account for 30.7% of the catalog total. Human impact is a separate comparison: the hazard ranks #3 for fatalities and contributes 10.1% of recorded deaths.

Geographic exposure is heavily concentrated in a handful of high-severity states. The three states absorbing the largest share of events are Texas (4,728 events, 338 fatalities), Missouri (2,399 events, 47 fatalities), Pennsylvania (2,288 events, 23 fatalities), reflecting both physical geography (coastal exposure, plains corridors, terrain) and dense population sitting directly in harm's way. At the other end, states such as Oregon, Guam, Alaska report far fewer events, a genuinely rare event outside the leading states, not merely an underreported one.

NOAA entries are reports filed by local National Weather Service offices. Counts therefore reflect both observed weather and reporting practice; they do not measure unreported events, household exposure, or the probability of a future event at one address.