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Real-time extreme snowfall and blizzard data from NASA EONET winter weather monitoring
View on Globe →Heavy snowfall events can pile snow up very quickly — sometimes faster than people can clear it away. A single powerful storm can drop over a metre of snow, burying cars and blocking roads for days. In some places, the weight of the snow can even cause roofs to collapse.
NASA satellites track snow cover globally every day, monitoring how winter snowpack builds up across mountains and polar regions. This data is critical not just for managing snow events, but for predicting spring floods — since mountain snow is a vital reservoir that releases water slowly as it melts.
NASA's MODIS instrument maps global snow cover every day using visible and near-infrared light, tracking snowlines as they advance and retreat across mountain ranges and polar regions. This daily snow cover product is used by water managers worldwide to estimate how much water is stored as snowpack — a crucial input for reservoir planning and flood prediction.
The AMSR-E and AMSR2 passive microwave sensors can detect the presence of snow beneath clouds that block optical cameras, providing continuous snow monitoring even during active storms when cloud cover is complete. The Global Precipitation Measurement (GPM) mission's Dual-frequency Precipitation Radar is the first space-borne radar capable of measuring falling snow rates from orbit, distinguishing snow from rain in storm systems.
Avalanche prediction teams in mountain regions use NASA satellite data alongside local weather observations to assess snow stability and issue warnings before slopes release. EONET tracks major snowfall events reported by national weather services and research institutions worldwide.
Earth Explorer displays major snow events tracked by NASA's EONET monitoring network. Significant blizzards, extreme snowfall events, and record-setting winter weather systems worldwide appear as glowing dots on the interactive globe.
View Live Snow Events →Snow forms when water vapour freezes directly into unique ice crystals at temperatures below 0°C. Sleet forms when snowflakes partially melt through a warm air layer and then refreeze into ice pellets. Freezing rain goes one step further — the drops stay liquid until they hit cold surfaces and instantly freeze, creating a dangerous layer of black ice. All three can occur in the same storm.
A blizzard is defined as a snowstorm with sustained winds of at least 56 km/h, visibility reduced to less than 400 metres, and these conditions lasting at least three hours. The combination of wind and snow creates whiteout conditions where you cannot see your hand in front of your face. Even a moderate amount of snow becomes very dangerous in blizzard conditions.
Major snowstorms can drop 30–60 cm in a single event. The record single-day snowfall was 193 cm at Silver Lake, Colorado, in 1921. Lake-effect snow near the Great Lakes regularly dumps over 150 cm in 24 hours because cold Arctic air picks up vast amounts of moisture crossing the relatively warm lakes. Some mountain towns in Japan and the Alps receive 10–15 metres of snow in a single winter.
Compacted snow is heavy — a cubic metre can weigh over 500 kg. This can collapse roofs, snap power lines, and bring down trees. Roads become slippery, causing accidents. Avalanches in mountain areas can bury people and entire buildings. Snow shovelling triggers a surprising number of heart attacks each winter because the combination of cold air and heavy lifting places great stress on the cardiovascular system.
Stock up on food, water, medication, batteries, and a phone charger before a forecast blizzard. Have a shovel, ice scraper, and sand or grit ready. Keep your vehicle's fuel tank at least half full. Plan for power outages and make sure carbon monoxide detectors work if you use backup heaters. Stay indoors during the storm and check on elderly neighbours before and after.
MODIS maps global snow cover daily using visible and near-infrared imaging. AMSR sensors detect snowpack through clouds using microwave signals. GPM's Dual-frequency Precipitation Radar — the first to measure snowfall rates from orbit — distinguishes snow from rain within storm systems. Together these tools give water managers and emergency agencies a complete picture of where and how much snow is falling and accumulating.