Hurricanes can grow by replacing their eyewall

All hurricanes have a central eye where no extreme weather phenomena take place

When standing in the eye of a hurricane, you're likely to experience sunny, cloudless skies surrounded by a wall of intense winds and thunderstorms. The physics behind this formation is the same as what causes water to spiral around a hollow cone as it goes down a drain.

Tropical cyclones consist of three main parts: the eye, the eyewall, and rainbands

The eye is a calm, clear central area surrounded by an eyewall of intense thunderstorms. Rainbands are spiral bands of clouds and thunderstorms extending from the eyewall.

How do hurricanes form?

Tropical cyclones, also called hurricanes and typhoons, cause catastrophic damage when they strike land. This four-minute video explores the life cycle of cyclones—how atmospheric conditions, ocean temperatures, and the Earth’s rotation combine to create them, and how they are driven by winds and eventually weaken after moving over land.

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.

Hurricanes, which rely on air consistently spinning in the same direction, cannot cross the equator because air curves in opposite directions north and south of it.

Nor'easters can produce thundersnow—lightning in blizzard conditions

Although thunderstorms typically require warm air to rise in updrafts and collide with heavier soft hail, which creates charge separation and eventual electrical discharge, these cyclones can replicate these conditions by churning the atmosphere through strong winds. Rarely, especially warm lakes can similarly help generate thunderstorms during the winter.

Hurricane conditions are created in a University of Miami wind-wave tank

The SUrge-STructure-Atmosphere INteraction Wind Wave Laboratory contains a 38,000-gallon wave pool connected to a wind tunnel that can generate air currents of up to 155 mph. SUSTAIN allows scientists to study how the atmosphere interacts with the ocean in extreme weather.

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.

The NOAA has a specialized team of researchers that fly directly into hurricanes

The reconnaissance missions gather data for computer models to forecast hurricanes and improve disaster preparedness. Each flight can last eight to ten hours and uses a specialized Air Force fleet.

Small elevation differences drastically protect homes in hurricanes

The construction of seaside homes has long involved building residences on elevated stilts, but this feature adds costs—and some elevated homes still fail. Explore the engineering behind the ideal height of a hurricane-proof building.

Project STORMFURY explored modifying hurricanes with silver iodide

Between 1962 and 1983, researchers at the National Oceanic and Atmospheric Administration investigated whether weakening and controlling hurricanes was possible. The investigation showed very few hurricanes met the criteria for modification, despite successfully weakening two storms.

How El Niño and La Niña affect the Pacific and Atlantic hurricane seasons

During El Niño, trade winds push warm waters across the Pacific toward northwest South America, affecting atmospheric circulation. The resulting strengthening of vertical wind speed and direction in the Atlantic basin disrupts hurricane formation, while the weakening of this wind shear in the central and eastern Pacific basins increases hurricane likelihood. El Niña, conversely, has the opposite impacts.

Watch a North Carolina house collapse into the ocean

While the Outer Banks experiences beach erosion, rip currents and overwash from a nor’easter along the coast, a seaside house in Rodanthe collapsed Tuesday.

Wind helps trees develop resistance to collapse

Scientists at Biosphere 2 found that trees grew faster in the facility than those in the wild but collapsed more quickly when replanted outdoors. Researchers uncovered that trees build resistance when pushed and pulled due to wind stress, strengthening their foundational root systems.

Watch a time-lapse of hard coral growth, which forms coral reefs

Over several weeks in an aquarium, these staghorn coral polyps grew and produced new polyps as they deposited calcium carbonate, which forms the basis of coral reefs. At the 0:28 mark, you can see coral growth healing a damaged branch.

How its uneven rotation produces the sun's 11-year cycle and flips its magnetic poles

While charged material rises and falls in the sun's convection zone, which induces magnetic fields, different latitudes rotate at different rates, making these fields increasingly turbulent. This builds to a critical point—the solar maximum—where magnetic field-driven events, such as solar flares, become more common before the field collapses and flips, restarting the cycle.

Jupiter’s size forced the creation of modified planetary formation models

Since solar winds remove gases from protoplanetary disks within millions of years of a star’s birth, models needed to provide a mechanism to jump-start Jupiter’s formation and growth. The solution involved incorporating pebbles of matter into the disk.

What will happen and what will remain of the sun when it dies

Upon exhausting the hydrogen fuel in its core, gravitational pressure will collapse and heat up, causing a surrounding layer to become hot enough to fuse hydrogen and release energy that swells the outer layers. This will turn the sun into a red giant that will engulf Mercury, Venus, and (likely) the Earth. These outer layers will eventually be shed, leaving behind a white dwarf.

An image of a shark swimming on the freeway repeatedly fools viewers during natural disasters

The long-running joke traces back to 2011, following Hurricane Irene in Puerto Rico. Since then, pranksters have spread the image after Hurricane Matthew in 2016, Hurricane Harvey in 2017, and Hurricane Laura in 2020. The image is photo-edited, combining a 2005 photo of a kayaker being followed by a great white shark and a photo of a flooded street.

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.

Under the Big Rip scenario, dark energy becomes strong enough to tear atoms apart

If the density of dark energy, which produces a repulsive effect through the expansion of space, increases with time, then all structures of matter, including galaxies, stars, planets, and atoms, will be pulled apart once the strength of dark energy surpasses the magnitude of the forces holding those structures together, including the gravitational and electromagnetic forces.

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

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.

Examining the causes of power outages, from system damage to preventative measures

Stray balloons, contact with trees, malfunctioning equipment, and severe weather are among the causes of failures that can cause widespread, unplanned blackouts. Although contingency options that rely on alternative transmission pathways to deliver electricity from generators to consumers may be possible, some shutoffs, brownouts—available power is reduced—and cycles of repeated outages may be intentionally implemented to protect public safety.

Microtears in muscles from exercise cause fibers to grow back larger

Placing muscle under increased load or stress causes damage that requires rest to repair, leading to stronger, more enduring muscle over time. Muscles adapt to such increasing demands by improving their efficiency with approaches that include increasing the number of mitochondria housed in hundreds of thousands of muscle cells.

Light waves can interfere and cancel each other out

When light waves travel past one another, their peaks and valleys combine, just as overlapping ripples in water can combine to form a larger ripple. When the peak of a light wave meets the valley of another of the same wavelength and brightness, the waves combine to produce no light.

As deposits build up under the eye, the retina bends with macular degeneration

The retina bends due to the accumulation of proteins and other materials beneath it. That's considered the milder "dry" form of macular degeneration. Another form, called "wet" macular degeneration, is caused by abnormal blood vessels leaking fluid into the eye, which can rapidly affect central vision.

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.

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.

Planeterrellas create artificial auroras that mimic the atmospheric displays of light by setting up an electric field between two metal balls in a jar filled with a small amount of air.

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

Fireworks make a loud booming sound after exploding due to air expanding faster than the speed of sound.

Gerrymandering works through two techniques: cracking opposing voters across districts to dilute their power, and packing them into a few to waste their votes in lopsided majorities.

Volcanoes 'die' when their supply of magma runs out, if they are shifted away from their underlying magma reservoir, or if they get clogged by collapsing or their magma cooling back into rock.

Poison ivy will likely become both larger and more resilient due to climate change.

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.

When caught in the mouths of cardinal fish, seed shrimp release glowing, bioluminescent chemicals, which alert predators of the cardinal fish, prompting the shrimp's ejection.

The syncytiotrophoblast is the outer layer of the placenta and the largest human cell, spanning an area about twice that of a king-sized bedsheet.

The first image of a black hole was captured by creating an Earth-sized virtual observatory from a network of eight radio telescopes.

Artificial coral reefs have been 3D printed from nontoxic, biodegradable terracotta clay, which coral polyps have used as a foundation for rebuilding marine ecosystems.

After 25 people used virtual reality headsets to practice flying with virtual wings—flapping their arms—their visual cortex responded to the wings almost as if they were real arms, treating them as body parts.

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

Hookworm infection, though risky, may help fight certain autoimmune conditions by tamping down the immune system's inflammatory response.

Before the current East Wing ballroom project, only two White House renovations in the past 100 years cost more than $10M.

To reduce wrinkles in clothing, research recommends gentle wash cycles with more water and tumble drying with smaller loads and longer times.

See how Ebola tore through Guinea, Sierra Leone, and Liberia in 2014-2016.

Long before Major League Baseball began allowing instant replay for balls and strikes, an umpire reluctantly used the technology to determine whether a hit was a home run, a move that inadvertently ushered in a new era for the sport.

Iran's Revolutionary Guard Corps is independent of Iran's regular army and is one of the most powerful and influential military-political organizations in the Middle East.

The original copy of the Declaration of Independence is not a pristine document, and even features a smudged anonymous handprint in the bottom left corner.

For centuries, it was common to sleep in two shifts: a few hours at the beginning of the night, and a longer period beginning around midnight