Natural disasters occur all the time—everything from hurricanes and tsunamis to blizzards, avalanches, and floods.
According to National Geographic, there are around 100,000 avalanches in the western United States annually, and the National Weather Service names flash floods specifically as the number one weather-related killer in the U.S.
One of the most dangerous things about flash floods is that they occur so quickly—hence their name—and are often underestimated. By the time the alert flashes on your phone, it might be too late.
In a recent example, a portion of Himalayan glacier broke off and caused an avalanche and catastrophic flooding in India on February 7. The incident was massive and destroyed one hydroelectric plant and damaged a second in addition to trapping several people in tunnels and killing several more. Because a flash flood can strike for a variety of reasons, it’s further proof to always take the threat of one seriously.
But what exactly is the difference between a flash flood and a normal flood? Let us explain.
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What Is a Flood?
Let’s start with the basics. A flood, as defined by the National Weather Service, is an “overflow of water onto normally dry land.” Flooding can stem from many places, like existing waterways. Rivers and streams can cause flooding in surrounding areas, and floods occur over a long period of time, ranging from days to weeks.
How Do Floods Form?
The most common assumption is rain, and while that’s true, it oversimplifies what is going on in most floods.
The midwestern floods of 2019, which affected around 14 million people in Nebraska, Missouri, South Dakota, Iowa, and Kansas, provides an example of how long it can take for floods to make themselves felt. The conditions on the ground started in 2018, when heavy rains saturated the soil. Then, the damp conditions on the ground stayed in place as the ground froze over during the winter, with snowfall piling on top.
“The higher-than-average precipitation, combined with warm temperatures, snowmelt and the frozen ground, was a perfect storm for flooding,” Mindy Beerends, a senior meteorologist at the Des Moines office of the National Weather Service, told The New York Times in March of 2019. “The ingredients were in place.”
And then quickly during the spring, temperatures started to rise and rain began to fall. While regions like Nebraska only got slightly more rain than the historical average, the water had nowhere to go because of the deeply saturated soil. The two inches of rain in some places was added on top of six inches of snowmelt.
How Are Flash Floods Different?
Flash floods are generally a surprise. While floods have any number of complex origins, flash floods typically stem from sudden, heavy rain. There are other sources as well, like a dam or levee collapsing. A flash flood is any sudden influx of water into a dry area, typically within six hours or less.
The National Weather Service says that “flash floods are usually characterized by raging torrents after heavy rains that rip through river beds, urban streets, or mountain canyons sweeping everything before them.”
What Do Flash Floods Look Like?
They vary greatly depending on storm and terrain, but the 1972 Rapid City, South Dakota, flash flood offers an example of their tremendous potential power.
On the evening of June 9, 1972, a massive storm moved west of Rapid City, on top of the nearby Black Hills, and a stunning 15 inches of rain fell. Even if the land was prepared to take an inch or so of water, it was quickly overwhelmed. Coming down from the Black Hills into the urban area, the water gained a horrifying momentum.
“There was so many [people] in trees and screaming and crying and the sparks were flying from electric wires, houses were on fire, it was just — it was hell,” said flood survivor Rita Rosales, speaking to NPR on the 40th anniversary of the disaster. Around 1 billion metric tons of water hit the area, destroying 5,000 vehicles, over 1,000 mobile and traditional homes, injuring over 3,000, and tragically causing 238 deaths.
Not every flash flood is as powerful as the one that rocked Rapid City, but they all have the potential to be dangerous. So the next time your phone is buzzing with an alert, heed the warning and stay safe.
Inflatable Boats If You Need an Escape
The Intex Seahawk 3 is a three-person boat that's a great balance of budget and quality. It's versatile, so you can use it for fishing, relaxing, or rowing, and it's heavy-duty thanks to puncture resistant PVC. It inflates and deflates easily and comes with two aluminum oars.
Heading out with a crowd? Opt for Intex's Excursion 5. This inflatable boat can hold up to five people, and it even comes with a motor mount fitting. The boat features three air chambers for extra buoyancy, and an I-Beam floor construction adds rigidity.
You don't have to spend a lot to get an inflatable boat to use this summer—this Intex model comes in under $50! The budget-friendly boat has a three-person capacity, comes with two oars, and includes a manual pump. It's not the most heavy-duty on our list, but if you're just looking for casual cruising, you can't beat this.
If you're heading out fishing, this is the inflatable boat for you. The pontoon-style boat features removable gear bags for storage (including 20 pockets and two drink holders), an anchor system, and a rod holder that can be mounted in six different positions. The seat mount and foot rests can adjust to a wide variety of lengths, and this boat also has a motor mount.
This six-person boat is the ultimate summer party spot. With a spacious lounge area and a front bow seat, you'll have plenty of room for your whole crew. It even has an inflatable rear swim platform! Sit back, relax, and cruise all day.
You don't have to spend a lot to get an inflatable boat to use this summer—this Intex model comes in under $30! The budget-friendly boat has a two-person capacity, comes with two oars, and includes a manual pump. It's not the most heavy-duty on our list, but if you're just looking for casual cruising, you can't beat this.
Heading out with a crowd? Opt for Intex's Excursion 4. This inflatable boat can hold up to four people, and it even comes with a motor mount fitting. The boat features three air chambers for extra buoyancy, and an I-Beam floor construction adds rigidity.
Heading out with a crowd? Opt for Intex's Excursion 5. This inflatable boat can hold up to five people, and it even comes with a motor mount fitting. The boat features three air chambers for extra buoyancy, and an I-Beam floor construction adds rigidity.
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David Grossman is a staff writer for PopularMechanics.com. He's previously written for The Verge, Rolling Stone, The New Republic and several other publications. He's based out of Brooklyn.
