Every hazard name in this archive comes from the NOAA Storm Events Database, where each event is filed under a fixed event type. Those names are precise, and they do not always mean what everyday speech means. This page explains the ones you will meet most often, with the count of records behind each.
Wind
- Thunderstorm Wind — straight-line winds produced by a thunderstorm downdraft, reported at 50 knots (58 mph) or more, or when they cause damage. The single most common record in the archive with over 566,000 entries. Not a tornado: the damage falls outward in one direction rather than converging.
- High Wind — sustained non-thunderstorm winds of 40 mph or more, or gusts of 58 mph, usually from a large pressure gradient rather than a single storm.
- Strong Wind — non-thunderstorm winds below High Wind criteria that still caused damage, injury or death.
Water
- Flash Flood — flooding that begins within roughly six hours of the rain that caused it, typically in creeks, urban drainage or after a dam failure. The deadliest flood category because it gives almost no warning time.
- Flood — slower river or areal flooding that develops over more than six hours and can persist for days.
- Heavy Rain — rainfall significant enough to be recorded but which did not produce flooding classed under the categories above.
Storms and ice
- Hail — logged when stones reach one inch in diameter (quarter size) or larger; the threshold rose from three-quarters of an inch in 2010, which is visible as a step in the yearly counts.
- Tornado — a violently rotating column of air in contact with both a cloud and the ground. Rated after the event by damage survey.
- Winter Storm / Heavy Snow / Winter Weather — three separate categories separated by severity and by which warning criteria were met, not by snowfall alone.
Two things worth knowing before reading any chart
- Coverage start dates differ. Tornado records begin in 1950, hail and thunderstorm wind in 1955, and most other categories only in 1996 when the database moved to its current structure. A hazard that looks new is usually just newly catalogued.
- Reports follow people. An event only enters the archive if somebody observed and reported it, so populated counties with dense spotter networks record more than empty ones experiencing the same weather. Our per-resident ranking exists to counterbalance exactly this.
See the methodology page for sources and known limits, or browse every hazard type with national totals.