Flood recurrence intervals are based on independent probabilities

Flood insurance policies from the National Flood Insurance Program cost just over $1,100 per year on average

Private residential policies range from $600 to $2,800 per year. Taking steps to lower flood risk in your home, such as installing flood vents or elevating home utilities, can make premiums cheaper.

Why do flash floods occur?

Flash flooding can be more dangerous than traditional floods, occurring within the span of hours and exhibiting rapid currents. Here's how atmospheric conditions and geography combine to make some locations ripe for the disaster.

Average hurricane intensity, not frequency, has increased over the past century

While the total number of tropical cyclones globally each year has not significantly shifted since 1920, a greater proportion of them are major, defined as category 3 or higher on the Saffir-Simpson scale. The increased energy present in a warmer climate may be contributing to higher intensification rates.

Earthquakes of identical magnitudes are unlikely to cause equal damage

The severity of earthquakes depends on factors beyond the energy released in a region, including local architecture and geological conditions, such as water-saturated soil behaving like quicksand. Secondary effects, such as landslides, floods, and fires, may also contribute.

On average, every in-service airplane is struck by lightning once a year

The average strikes per surface area per year on Earth suggest that aircraft should only be struck once every 1,000 years, based on their size, but proximity to storm clouds' high electrical fields increases strike rates. Aircraft are designed as continuous conductive shells, causing electricity to flow along their exterior and preventing internal damage.

Since 1600, the longest stretch without an outbreak that killed 10,000 was four years

We think of pandemics as unlikely events, but disease outbreaks are surprisingly common. Over the past 400 years, the longest stretch without an outbreak that killed at least 10,000 people was just four years. The next pandemic can't be precisely known, so experts and policymakers focus on preparation.

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.

Learn why water can take millions of years to be recycled via the hydrologic cycle

While a single drop of water spends an average of nine days in the atmosphere before precipitating back to Earth, it can spend thousands of years in the ocean before evaporating, and hundreds of thousands of years deep in rock layers before being released as steam in volcanic eruptions. Some water molecules have been trapped in Antarctic ice sheets for millions of years since they last moved through the water cycle.

Tree rings can reveal centuries of environmental change and natural events

The width and shape of tree rings reflect yearly growth conditions like rainfall or snowfall. Scars in the rings can record disruptions such as fires, avalanches, or earthquakes, explaining when and how those events occurred.

Stroke risk doubles each decade after age 55

While age is the greatest risk factor, genetics, diet, and overall health play a prominent role in determining individual stroke risk. Prevention focuses heavily on modifiable risk factors. High blood pressure is the single most important controllable risk factor, contributing to both types of stroke.

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

One theory suggests real estate markets follow a predictable 18-year pattern

The theory dictates that real estate markets tend to experience about 14 years of growth, including a mid-cycle dip, then experience four years of decline. Real estate experts in London discuss the theory in an article.

Niagara Falls is slowly eroding backward toward Lake Erie

At its current erosion rate of roughly one foot per year, Niagara Falls is expected to retreat all the way to Lake Erie in about 50,000 years.

A database tracking water conflicts for thousands of years

This open-source database has logged more than 4,000 conflicts around water across 100 countries, cataloging water as a casualty, trigger, or weapon of the conflict.

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

Some renewable energy sources may weaken the resiliency of electric grids by removing outage buffers provided by coal- and natural gas-fired plants, which provide the system with more time to find a new power source if a plant goes down.

Florida reports 71 imported malaria cases annually—4% of all the US cases

The Sunshine State reports an average of 71 imported malaria cases annually. Malaria isn't endemic to Florida but mosquitoes in the state are biologically capable of transmitting the disease from one infected person to another noninfected person.

Some renewable energy sources may weaken the resiliency of electric grids by removing outage buffers provided by coal- and natural gas-fired plants, which provide the system with more time to find a new power source if a plant goes down.

The census reshapes House representation every 10 years

Conducted once every 10 years, the US Census determines how House seats are reapportioned among the states. The 2020 results shifted representation as state population growth and decline altered the geographic balance of political power.

NOAA's interactive sea level rise viewer

How will rising seas affect you? Launch NOAA's sea level rise viewer and zoom in on impacts to different parts of the United States, or type in your city or address to learn more.

The 2025 Social Security Trustees Reports reaffirmed that beneficiaries will be paid 100% of total scheduled benefits until 2033

Specifically, it noted that the Old-Age and Survivors Insurance Trust Fund will be able to pay 100 percent of total scheduled benefits until 2033, which was unchanged from the previous year’s report.

Microplastics from sewage sludge persist in farmland soil for decades

A 25-year study in Scotland found that sewage sludge used as fertilizer introduces various microplastics into soil, where they remain and degrade into smaller particles that worsen soil quality. Dyes found in microplastics may also be leaching into the environment, causing additional toxic effects.

Ramadan will be celebrated twice in 2030 due to the 33-year lunar cycle

Because the Islamic year is 11 days shorter than the Gregorian calendar, Ramadan migrates through every season over a 33-year cycle. In 2030, it will fall twice in the same Gregorian year.

80% of a VC firm's returns come from 20% of the deals, per VC's 'power law'

Early-stage startups are highly risky investments. Many companies in a VC portfolio will not provide any significant return.

Compounding, explained

During conversations about personal finance, the term "compounding" gets thrown around—but not everyone understands how compound interest and compound returns work. Broadly speaking, compounding is what happens when you not only earn returns or interest on your original investment, but also on the accumulated returns or interest you receive over time. This article explains how both of these processes function, and what compounding could mean for your wallet.

Why train derailments happen, 101

In 2021 alone, there were over 1,000 reported derailments in the US—and no amount of maneuvering will reduce those numbers to zero. This 101 explains the causes of train derailments and how safety protocols look to limit them each year.

Keep track of how many of the '100 best films' you've seen

This list from the AFI, a nonprofit dedicated to the cinematic arts, ranks the 100 best films of the past 100 years. A jury of 1,500 film experts compiled the list and includes movies from nearly every genre. It’s also an interactive checklist, allowing you to keep track of how many of the films you’ve seen.

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

View the ten deadliest tornadoes in US history.

Coral polyps reproduce via broadcast spawning, where entire reefs simultaneously release reproductive cells for about one hour, once a year.

US housing costs have risen by roughly 175% between 1991 and 2026—but a growing number of Gen Zers are becoming homeowners anyway. In 2025, 4% of homebuyers were Gen Z, up from 3% the year before.

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.

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.

Despite being favored by 87% of Americans, Congress does not have term limits.

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.

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

Apeirophobia is an overwhelming fear of living forever, perhaps stemming from the brain's inability to conceptualize an infinite life.

Indefinite cloning of some endangered species may not sustain their longevity because cloning success rates decrease as genetic mutations accumulate.

The American Society of Civil Engineers' infrastructure report card gave the US a C in 2025, its highest grade since the project launched in 1998.

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.

Explore a list of the 100 best novels of all time, compiled by some of the world's best living writers, including Salman Rushdie, Stephen King, and Jennifer Egan.

Between 10 million and 50 million people in the US develop rashes from poison ivy, poison sumac, and poison oak each year.

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

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.

Researchers believe the brain consolidates memories, processes emotions, and plans for the future during dream states

Dozens of S&P 500 stocks, including Coca-Cola and Walmart—known as the dividend aristocrats—have increased dividends every year for 25 years

44% of Americans say they pray at least once a day—discover how your state's religiosity stacks up against the rest of the country.

Hear 50 years of iconic hip-hop samples, the genre's foundational looped tracks

In 1963, a basement renovation in Turkey revealed a passageway to a hidden, multilevel underground city that once housed as many as 20,000 people

Some coin denominations have ridges etched on their sides, partly to prevent counterfeiting, in a practice called 'reeding.'