12 Flash Floods That Came Out of Nowhere and Took Everyone by Surprise
Flash floods strike with little to no warning, turning calm streets into raging rivers in minutes and leaving devastation in their wake.
- Alyana Aguja
- 4 min read
Perhaps one of the most dangerous disasters, flash floods are capable of turning ordinary landscapes into raging torrents in a matter of minutes. Often caused by heavy rainfall, dam failure, or overflowed drainage systems, they occur with little warning, sweeping away everything in its path–homes, vehicles, and lives. From ancient tragedies such as the Johnstown Flood to contemporary disasters in cities across the globe, these tragedies are grim reminders of water’s unrelenting power and the necessity of perpetual watchfulness.
1. Rapid City, South Dakota (1972)
Image from National Weather Service
A freak midnight rainstorm dropped 12 inches of rain in six hours and overwhelmed Canyon Lake Dam. The dam failed, releasing a wall of water that devastated Rapid City, taking 238 lives. Most of the victims were sleeping when they were caught, receiving little or no warning of the tragedy.
2. Johnstown, Pennsylvania (1889)
Image from Wikipedia
The South Fork Dam burst after several days of nonstop rain, sending a 40-foot-high wall of water hurtling toward Johnstown at rates of as much as 40 mph. The flood washed houses, factories, and entire families away, killing more than 2,200 people. Eyewitnesses reported a deafening roar before the water obliterated everything in its path.
3. Big Thompson Canyon, Colorado (1976)
Image from Videos Index on TIME.com
A freak storm brought 12 inches of rain in less than four hours, producing a lethal surge down Big Thompson Canyon. The waters rose so rapidly that few individuals had time to flee, causing 144 fatalities. Cars, houses, and even large pieces of highway were swept away in the mayhem.
4. Las Vegas, Nevada (1999)
Image from Las Vegas Review-Journal
Despite its arid climate, Las Vegas suffered a devastating flash flood when a ferocious thunderstorm dropped several inches of rain within an hour. The city’s drainage system was overwhelmed, flooding streets into raging rivers and washing away automobiles. Numerous tourists and residents were unprepared, with two losing their lives.
5. Shadyside, Ohio (1990)
Image from The Intelligencer
A thunderstorm lingered over Belmont County, leaving nearly five inches of rain in less than one hour. The ensuing flash flood carried a wall of water down Pipe and Wegee Creeks, obliterating houses and taking 26 lives. Neighborhoods were erased in a matter of minutes.
6. Lynmouth, England (1952)
Image from Lynton & Lynmouth
A rain-soaked storm passed slowly, delivering nine inches of rain in one day. The rain filled rivers with torrents crashing into the seaside village of Lynmouth. The bridges were destroyed, houses collapsed, and 34 lives were lost as the deluge swept them out to sea. Those who survived called it an unexpected “wall of death” that descended upon them.
7. Tbilisi, Georgia (2015)
Image from AGU Blogosphere
A massive overnight storm caused the Vere River to surge violently, flooding Tbilisi’s streets and destroying homes and a zoo. More than a dozen people were killed, and zoo animals that escaped, including lions and tigers, roamed the city. Some animals were later found miles away, disoriented by the flood’s power.
8. Ellicott City, Maryland (2016)
Image from Wikipedia
A freak storm dropped six inches of rain over a span of two hours, converting the old downtown district into a torrential river. Autos drifted down Main Street as stores were ravaged, killing two individuals. The flood was so strong that it took years for the town to return to normal.
9. Sentani, Indonesia (2019)
Image from Reuters
Heavy rain caused abrupt flash floods and landslides, which ran through villages in Indonesia’s Papua. More than 100 lives were lost, with whole neighborhoods covered in mud and debris. The water was so powerful that it swept away trees, boulders, and even houses downriver.
10. Nashville, Tennessee (2010)
Image from Frist Art Museum
A record 13.6 inches of rain in 36 hours overflowed the Cumberland River and inundated downtown Nashville. The Opryland Hotel was fully submerged, and 26 people died in the sudden catastrophe. Flood damage totaled over $2 billion, one of the most expensive in U.S. history.
11. Gardner, Illinois (1996)
Image from Belleville News-Democrat
A wall of water swept through the tiny town following a levee breach that sent a sudden rush from the Mazon River. The unexpected flood left residents stranded on rooftops and washed away cars. Although no one was killed, the town incurred millions in damages within hours.
12. Zaragoza, Spain (2015)
Image from FloodList
A freak summer storm unleashed torrents of rain in northeastern Spain, transforming usually parched riverbeds into murderous torrents. The floodwaters coursed so swiftly that cars and livestock were swept away in minutes. Despite emergency responses, the surprise flooding claimed a few lives and wiped out whole communities.