Avalanches happen when layered snow fails, often on perfect ski slopes

Avalanches, which kill an average of 27 people in the US each year, typically require mountain slopes between 30 and 45 degrees and a layer of sturdy snow atop a weak, unstable layer, which can be put into motion by a trigger.

After a landslide, repeat activity may follow the appearance of cracks, springs of water, or dirt, sand, and rocks tumbling down from scars—exposed portions of Earth where the initial landslide began.

While landslides are associated with the downward flow of unstable terrain, the term encompasses a variety of geological processes, which are distinguished by how the material moves and what materials are involved.

Ski mountaineering—or 'skimo'—debuted at the 2026 Winter Olympics

The sport involves skiing both uphill and downhill, with sections where the skis are strapped to the athlete's back. Skiers start at the bottom with a carpet-like layer on their skis to help ascend, remove them for the final climb, and then step back into normal skis for a slalom-like descent.

Explosive volcanic eruptions happen when magma pressure overcomes rock strength

Magma usually stays underground because of a balance between its upward pressure, the weight of the Earth’s crust above, and the crust’s rock strength. Landslides can reduce crust weight, while built-up gas pressure can strengthen magmastatic pressure.

Explaining the icy mystery of the Dyatlov Pass deaths

A decades-old mystery from Soviet Russia could be explained by studying the science of snow. After nine students died on a hiking trip in the Ural Mountains, Soviet investigators found six had perished from hypothermia while three others died from blunt force trauma. The mystery confounded officials for years, and rumors of yeti attacks and similar theories abounded until researchers proposed a new potential culprit: an avalanche.

See how the Winter X Games course is built

Winter X Games courses are custom-built over weeks, with crews moving thousands of tons of snow to create features like halfpipes and jumps—incorporating athlete input to ensure challenging designs that push progression and safety.

The steep and slippery Russian ice slides sparked centuries-long obsessions with thrill-seeking

When a French traveler happened upon the 17th and 18th century Russian pastime of sledding down man-made hills, he brought the idea home and inspired others to modernize the mechanics. Adoration for coasters spread around Europe and eventually reached the US, where the scream machine would undergo major advancements.

Some tectonic plates move faster than their underlying convection currents

Like a chain slipping off a ledge, as tectonic plates sink, their weight can pull the rest of the trailing plate forward, accelerating their movement. Plates can also break apart and fall, creating a suction effect that drives movement, resembling leaves following a passing car.

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.

Eruption forecasting relies on probabilistic methods resembling weather forecasting

While some volcanoes erupt with predictable signs, such as surface deformation from the build-up of underground magma pressure, others release magma at inconsistent rates. Extensive monitoring is needed to identify less clear patterns and indicators of future eruptions.

Although the term 'glacial pace' is associated with the slow movement of glaciers, during glacier surging, these massive bodies of ice can move over 60 meters (200 feet) a day.

Is ice slippery because of amorphization—a chaos of molecules caused by sliding?

Traditional explanations cite three factors that make ice slippery: pressure, friction and so-called premelting. A fourth has been proposed in recent years: amorphization, that sliding along some surfaces creates molecular disorder, causing liquid-like behavior.

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.

Glacial ice loss can be determined by listening to escaping bubbles

Glaciers form from the accumulation of layers of snowfall over hundreds to thousands of years, trapping air bubbles that serve as time capsules of atmospheric conditions at the time. When glaciers melt, these bubbles produce a distinctive sound that can be detected by underwater microphones, allowing assessment of melting from a safe distance.

Lava flow viscosity plays a significant role in the type of volcano formed

Thin, runny flows spread quickly before cooling, producing expansive layers that build over time into wide shield volcanoes. The ejection and fast hardening of thicker lava flows and pyroclastic material create steep slopes and the characteristic cone shape of composite volcanoes.

Volcanic ash is composed of fragments of volcanic rock, minerals, and glass

These abrasive particles are hazardous to aircraft. They can melt within engines and re-solidify on turbine blades, preventing forward propulsion. If inhaled, chemicals within ash can be toxic, and the particles can embed themselves into the lungs' ducts, causing suffocation.

Winter Olympic sports highlight various laws and principles of physics

Figure skaters leverage the conservation of angular momentum during spins by tightening their bodies, and the skintight suits used in ski jumping help reduce drag. Centripetal force allows speedskaters to make tight turns, while friction on skis helps ski mountaineers climb slopes. No action can violate the conservation of energy.

Tectonic earthquakes are caused by tectonic plates sliding past one another at fault zones, deforming rock through friction as energy builds like a stretched rubber band.

Supervolcanoes can eject enough material to fill one-fourth of the Grand Canyon

Although extremely rare, their released material can trigger winters by blocking the sun and cooling the Earth’s surface for years. The Toba supereruption 74,000 years ago disrupted food chains and reduced the human population to a few thousand.

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.

Simulations suggest ice's slipperiness comes from rearranging molecules

Past models have proposed that slipperiness arises from a thin layer of liquid water formed at the ice's surface by frictional melting. However, new research suggests that electromagnetic forces between interacting surfaces push water molecules out of an ordered, crystalline structure and into a shapeless, soft, slippery layer. This process occurs solely through contact, independent of pressure or friction.

Davos is also one of Europe’s most well-known winter sports destinations

Davos emerged as a winter sports resort in 1865. The town went on to pioneer modern skiing, ski lifts, tobogganing, and ice sports. The city hosted early ski races, invented key lift technology, and became home to traditions like the Parsenn Derby and the Spengler Cup.

Ancient sunken plates may influence mantle convection and surface motion

Research suggests sunken tectonic plates can collide, assemble, and break apart to form structures called large low-velocity provinces. LLVPs can significantly enrich rising magma plumes with elements commonly seen on Earth’s surface.

The ingredients that make up severe weather

A seven-minute video illustrating how a storm is made. These factors—moisture, instability, lift, and shear—are explained through a series of data sets and creative, descriptive diagrams.

The fragility of the alpine tundra

This article takes readers into Rocky Mountain National Park's Alpine Tundra, an area above the tree line where only specially adapted plants can survive. One such plant is the cushion plant, which avoids strong winds by growing close to the ground...

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.

'Watermelon snow'—patches of pink, orange, and red in snow—is the result of extremophilic green algae that thrive in extremely frigid conditions and take the shape of red spheres in winter.

Snowflakes form when water vapor turns directly into ice

Every water molecule has a slightly bent shape due to electron repulsion and regularly forms bonds with hydrogen molecules. When they freeze, they form a six-sided (or hexagonal) lattice, resulting in the six-sided symmetry of snowflakes. As the snowflake falls, more water molecules freeze onto its six sides, forming the unique, beautiful geometric designs.

Crackling, popping, and rustling sounds have been reported during auroras

At the altitudes where auroras take place—between 100 and 300 kilometers (62 to 186 miles)—air is not dense enough to efficiently vibrate and carry sound waves to the ground. However, one theory suggests that the geomagnetic energy behind auroras can trigger electrical discharges near the surface, which may be the cause of reported sounds.

Extraterrestrial volcanoes spew material present during their formation

Unlike Earth's volcanoes that release lava, cryovolcanoes on distant moons erupt cold jets of water, ammonia, and other light gases present during the formation of their host planet. The movement of internal heat produced during formation is thought to drive icy plume movement.

Hail forms in freezing temperatures thousands of feet above the ground

Even if surface temperatures are well above freezing during the summer, updrafts during thunderstorms can push raindrops high into the atmosphere, where they can freeze and form hail. Giant hailstones the size of softballs require updrafts of close to 100 mph.

Six stories of survivors who fell from the sky

Rarely are there survivors when airplanes explode in air or crash due to the extreme speeds and elevation of the craft. Sometimes, though, people survive. Here are six stories of people who defied the odds and lived after falling from a plane.

The San Andreas Fault is an example of tectonic plates sliding past each other

The transform boundary divides the opposing movements of the Pacific and North American tectonic plates, which create shear zones that distort and fracture rock. These movements produce shallow earthquakes as rocks are gradually displaced hundreds of miles.

The economics of ski resorts

More than 480 ski resorts pack in nearly 65 million visitors each year in the US for historically high prices. Daily lift tickets may cost three figures at many locations. Amid industry consolidation and more stringent land use regulations, ski resorts are upping their prices—a factor that does not appear to be dampening the sport's popularity. Learn more here.

Switzerland's glaciers have lost ice volume every year since 2001

The trajectory of global warming is projected to cause three-quarters of the country's glaciers to be lost by 2100. Accelerated glacial melting worldwide affects as many as 800 million people who rely on meltwater for agriculture and personal use.

In the US, flash floods—rapid floods that occur within six hours of rain—kill more people than tornadoes, hurricanes, and lightning.

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.

Volcanoes can be active, dormant, or extinct based on the recency of eruptions

Active volcanoes may be in the process of erupting or expected to erupt in the future, having done so within the past 11,650 years. Dormant volcanoes have no short-term eruption history, but are expected to erupt in the future, while extinct volcanoes lack the history and expectation.

The complex science of snow removal

Plowing snow seems simple, but its actually a technically complex task and requires significant logistics, patience, and funding. New York City's 19,000 miles of roads require days to plow at a cost of $12M per inch of fallen snow, and roughly 17 million tons of salt were applied to road surfaces across the US in a recent year. Dive into the details of snow removal with an in-depth and funny video.

One halfpipe skier qualified for the Olympics via loopholes

Freestyle skier Elizabeth Swaney reached the 2018 Winter Olympics by completing safe, trick-free halfpipe runs and accumulating ranking points in low-participation events. The story, told humorously in this brief video, highlights how qualification systems can reward persistence and rule optimization over peak athletic performance.

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.

The composition of magma affects the explosivity of volcanic eruptions

Silicate-rich magma contains extensive molecular chains that trap dissolved gases like water and carbon dioxide. These gases build pressure until they violently escape, creating explosive eruptions. Low-silica magmas produce gentler eruptions categorized as effusive.

Lightning is the sudden flow of electricity in the atmosphere as two oppositely charged regions seek to become balanced via the movement of electrons.

Scientists monitor volcanoes with a suitcase-sized observatory called SKATE

Short for Setup for the Kinematic Acquisition of Explosive Eruptions, the device is left to record heat, sound and visual data while volcanologists remain at a safe distance. The $58,000 tool is the successor to the FAMoUS (Fast Multiparametric Setup) prototype.

What causes hail?

Hail can be a particularly destructive element of certain thunderstorms, occurring even during otherwise warm days. Learn about the dynamics that lead to ice chunks falling from the sky.

Quicksand—a mixture of sand with clay or silt soaked in water that gives way when enough pressure is applied—is denser than the human body, meaning you naturally float inside it.

In a tornado outbreak, a single severe weather system can spawn multiple twisters

By maintaining the ingredients for tornadoes—differences in wind speed and direction across altitudes, moisture, and rising air—for long periods of time as it moves across a region, a severe thunderstorm can continuously produce tornadoes by lifting multiple columns of horizontally rotating air.

Sinkholes form when underground cavities cause the surface above to collapse

These openings are typically carved by acidic water, which often forms in limestone-rich areas. However, leaking pipes, groundwater removal and extreme weather or geological activity increases the frequency of sinkhole appearances.

The first Winter X Games launched in 1997 at Big Bear Lake

The inaugural Winter X Games in 1997 introduced snowboarding, skiing, and snowmobile events—helping boost winter action sports’ popularity and paving the way for snowboarding’s inclusion in the 1998 Winter Olympics.