Why do flash floods occur?

Rapid intensification can cause hurricanes to increase by two categories in 24 hours

Rapid intensification is a 35 mph or more increase in a hurricane's sustained wind speed within 24 hours. The phenomenon is expected to become more common, resulting in more storms becoming life-threatening faster than people can modify their preparations for the increased intensity.

Flood recurrence intervals are based on independent probabilities

The term "100-year flood" does not mean the event will only occur once every 100 years, but it has a 1% chance of occurring in any given year. Soil saturation, watershed size, and urban development can impact flood severity.

Heat is the leading cause of death in natural disasters

Floods are a distant second, followed by hurricanes. That's according to data reported by the National Oceanic and Atmospheric Administration.

Learn all about different types of extreme weather

Find out in more detail about different types of extreme weather, from flooding to thunderstorms, from tropical cyclones to sandstorms, and more (w/ helpful videos).

Dirty lightning is a thunderstorm created from friction between rising and falling flows of ash and smoke during volcanic eruptions.

Fast-changing conditions during their formation make tornado forecasting difficult

The final steps of tornadogenesis—the process of forming a tornado—depend on near-surface details, such as local geography, which are difficult for radar to observe and affect how funnel clouds make contact with the ground. Inconsistencies in storm behavior have limited the amount of advance warning people receive before tornadoes touch down.

Whirlpool Rapids formed in a matter of days during the last ice age

Niagara Falls' dramatic whirlpool rapids were created in a matter of weeks when the retreating Falls intersected a buried ice age riverbed—generating North America's largest standing waves.

The deadliest aspect of volcanic eruptions is often not lava, but pyroclastic flows—avalanches of ash, gas, and rock that can move more than half the speed of sound.

The deadliest aspect of volcanic eruptions is often not lava, but pyroclastic flows—avalanches of ash, gas, and rock that can move more than half the speed of sound.

Extreme weather conditions heighten cholera risks in settings like refugee camps

Runoff from sewage—exacerbated by situations like flooding or extreme rains—heightens this threat. Increasing temperatures also create the ideal conditions for the bacteria to reproduce, increasing transmission risks.

There are no outdoor locations that are safe from lightning

If your hair stands up amid an approaching storm, seek shelter immediately, as a local buildup of charge imbalance precedes cloud-to-ground lightning. If you are stuck outside, move to a lower altitude, such as a valley or ravine, and avoid open fields, water, and isolated tall objects. Do not lie down or crouch.

City structures cause localized heat zones hotter than nearby rural areas

Urban materials like asphalt and concrete trap heat, while cities lack cooling features like trees and water. Due to hot runoff, urban streams can heat up by as much as 18°F more than forested streams.

The Federal Emergency Management Agency leads the US response to disasters

Established in 1979, FEMA coordinates the government's response to hurricanes, wildfires, floods, and other disasters, providing funding, logistical support, and recovery assistance. In FY 2024, the agency spent $35.1B, nearly 40% of the Department of Homeland Security's total budget.

Fossils form in environments where dead organisms can be rapidly buried

Such landscapes enable corpses to be encased by terrain before significant decay occurs. They are most commonly found in river deltas and sinking coastal regions, where sediments accumulate over time until geological forces expose the areas to erosion, revealing embedded fossils.

Favorable conditions for wildfires are becoming more frequent in the western US

A new study of the American West shows that climate change is driving more days that are hot, dry, and windy—the perfect conditions for deadly wildfires.

Hydroplaning occurs when a vehicle's tires lose traction on wet roads

Water depth must be over 0.1 inches, and vehicle speed must exceed 50 mph for hydroplaning to occur. Tire wear, size, and tread patterns affect the likelihood of hydroplaning, which is more common for all-wheel drive vehicles.

For centuries, Niagara Falls has been a magnet for daredevils seeking to conquer one of nature's most powerful wonders, with its 200-foot drop and water rushing at 32 feet per second with 280 tons of force.

Why is hydropower important when other power sources go dark?

Hydropower can ramp up, recoup shortfalls, and stabilize the grid nearly instantaneously. A new study quantifies the energy source’s contribution to grid stability.

The floating homes of Holland

Floating communities like Schoonschip in Amsterdam are offering a novel approach to combat climate change-induced flooding. With sea levels rising and storms becoming more intense, these floating neighborhoods are providing a sustainable flood defense solution. Learn how they work here.

Distinguishing between various solar surface phenomena, including solar flares and sunspots

Flares are sudden eruptions of electromagnetic radiation caused by a buildup of magnetic energy in the sun's atmosphere and often occur near sunspots, where strong magnetic fields limit the flow of hot material, creating these cooler regions. Flares can also be accompanied by coronal mass ejections—large explosions of plasma from the sun's upper atmosphere with their own magnetic fields.

Boomerang earthquakes reverse direction and ripple back the way they came

Computer simulations show that rapid changes in friction along a fault where an earthquake has traveled for long distances can produce a smaller quake in the opposite direction. Data consistent with the phenomena has only been recorded a handful of times from 2011 to 2023.

Venezuela's Lake Maracaibo is considered the lightning capital of the world

Spread across 140 to 160 nights, and as many as 10 hours per night, the region where the Catatumbo River flows into the semi-enclosed bay experiences approximately 1.6 million lightning strikes annually. The frequency of strikes may originate from warm Caribbean air interacting with cooler air from the Andes.

Tiny water droplets can blur a rainbow's colors into a foggy white

When sunlight enters water droplets, it can reflect from the inside and spread out into different colors, producing a series of colorful arcs—supernumerary bows—which we refer to as rainbows. For droplets a few hundredths of a millimeter in size, these arcs overlap onto each other, producing fogbows of white light.

Explore an interactive map of historical volcanoes, earthquakes, and tsunamis

The Natural Hazards Viewer allows users to map the locations of major natural hazards from 2150 BCE to the present. Advanced filters allow for various refinement methods, including volcano morphology, earthquake magnitude, tsunami height, deaths, and damage.

Why is the Amazon rainforest important?

Watch this five-minute video from National Geographic to learn about the importance of the Amazon rainforest and the risk of what's to come if humans continue to deforest it. The Amazon rainforest is about the same size as the continental United...

Panic attacks are intense fear episodes that often occur without a clear trigger

Unlike typical fear responses to real danger, panic attacks can mimic serious health problems, such as heart attacks. Sweating during a panic attack may seem random, but it's a leftover survival mechanism that made it easier for our ancestors to escape by slipping out of an attacker’s grasp.

Major genetic shifts in flu viruses can spark global pandemics

Antigenic shift happens when two different influenza viruses infect the same host and swap genetic material. The result is a brand-new subtype of influenza which, if easily spread among people, can trigger a worldwide pandemic.

Although rare, HFMD can spreads in pools due to poor bathroom hygiene

In pools with inadequate levels of chlorine, this disease can spread via the poop-to-mouth route, though this isn't one of the most common ways the disease is transmitted. People can become infected by swallowing contaminated pool water after little kids (or their parents) don't do an adequate job removing virus-laden feces from the child before the child enters the water.

Discover the catastrophic consequences of a failure of the US electrical grid—something that is more likely than many Americans think.

While El Niño moves warm Pacific Ocean waters east along the equator, La Niña moves them west, shifting where rainfall will become more common for months.

Chaos theory—informally known as the butterfly effect—is the reason why weather forecasts are presented with probabilities rather than certainties.

View the ten deadliest tornadoes in US history.

Watch how viruses like Ebola can spill over from animals to humans—and vice-versa.

Massive blooms of microscopic plankton called dinoflagellates produce the neon blue light seen in glowing tides.

An investigation suggests a Scottish island became awash in forever chemicals via seafoam and seaspray—raising questions about what that means for the safety of other coastal areas.

The boiling temperature of water decreases with increasing elevation because the molecules need less energy to overcome the lower atmospheric pressure associated with thinner air.

All rainbows are 'raincircles' caused by water droplets separating white sunlight into a spectrum of colors, but Earth's surface blocks the bottom half of the circle from our line of sight.

About 12.5% of US adults experience a phobia in their lifetime, a diagnosis that hinges on the intense fear interfering with daily life and persisting for at least six months.

Fireworks-related ER visits are on the rise—in 2024, they increased by 52% as compared to the prior year.

Poison ivy's rash-causing compound is found in the plant's roots, stem, and leaves—so coming into contact with any part of the plant can lead to rashes for the 85% of people who are allergic to it.

How fusion—which releases energy when two lighter atoms combine to form a heavier atom—differs from fission

Shooting stars, or meteors, are fragments of asteroids and comets that burn up as they enter Earth's atmosphere, creating streaks in the sky called meteor showers.

A 2019 Facebook event called on attendees to "Storm Area 51, They Can't Stop All of Us," resulting in countless memes, the creation of a music festival, and eventually the arrests of those who did try to approach the area.

Hedge funds, the private investment firms that trade a wide swath of financial assets, make money by imposing steep fees on investors and from the fund's investment performance.

How Amazon operates a 'flywheel' business model, a self-reinforcing cycle that drives continuous growth

Domino's Pizza's 30-minute delivery guarantee was responsible for the chain's 1980s surge, but it was discontinued after the company was found liable for delivery driver accidents.

Studies suggest when you sleep is as important as how much you get, and syncing with your circadian rhythms may lead to less fatigue and improved long-term health outcomes

The 19th-century painters of the Hudson River School were among the first American romantics, with portraits that displayed the natural beauty of the young country.

Explore the archaeological treasures of Pompeii, the city buried under volcanic ash when Mount Vesuvius erupted in 79 CE.

Frank Lloyd Wright's houses are historically hard to sell because they're old, subject to local landmark commissions, and often unfashionable