Severe Weather


Around the world, severe thunderstorms can occur year-round but are focused primarily in the local warm season, accompanied by heavy rains and dangerous lightning, and sometimes by large hail, damaging winds, and tornadoes.  In the United States, severe thunderstorms are defined as those that produce hail reaching a size of at least one inch (2.54 cm) in diameter, produce a wind gust of at least 58 miles per hour (26 m s-1), or a tornado.  They are often accompanied by widespread lightning capable of injury to people on the ground, damage to electrical infrastructure and power outages, and initiation of wildfires.  Wildfire threats are particularly high in the dry and mountainous west, where lightning-triggered wildfires can spread rapidly.  Distinct severe weather seasons are focused in the southeastern states in the fall and early spring, followed by a seasonal migration of severe weather into the central United States through mid and late summer.  

Impacts of severe weather can be observed through a variety of NASA remote sensing systems with products relevant to hazard monitoring, assessment, and recovery.  The Global Precipitation Measurement (GPM) mission and a broader international constellation of passive microwave sensors can be used to map thunderstorm cores and areas of heavy, perhaps flooding precipitation through the Integrated Multi-Satellite Retrievals for GPM (IMERG) dataset.  When heavy rains persist over time and flooding is of concern, precipitation estimates from IMERG can be combined with streamflow and inundation models to assist end users with predicting the likelihood and extent of river flooding.  To validate these models and assist with flood mapping, measurements of visible and near-infrared land surface reflectance from NASA’s MODIS aboard the NASA Aqua and Terra missions, the NASA/NOAA VIIRS instrument aboard the Suomi National Polar-orbiting Partnership (S-NPP) mission, and the multispectral imagers aboard the Landsat-7 and Landsat-8 missions can be used to map flood water extent.  Active remote sensing, such as synthetic aperture radar measurements from the European Space Agency’s Sentinel-1A and Sentinel-1B platforms, or data from other international partners can be used to provide mapping of flood water through cloudy scenes that frequently occur with heavy rainfall events.  In addition, damage to the land surface can be observed from these sensors, helping to map damage from long-track and intense tornadoes or extensive hail scarring of vegetation, assisting with geospatial analysis and quantification of crop or insurance losses.  In some cases, changes in the land surface as a result of severe weather can be long-term with recovery mapped over subsequent years by NASA and partnering agencies.

Latest Updates

October 21, 2020
A team of NASA researchers used this satellite and radar imagery to help officials in Iowa better understand the effects of a derecho that ripped through the state in August. Credits: NASA, University of Oklahoma, the NOAA Storm Prediction Center, Nationa
An intense August storm gave many Iowans a brief sense of what it might feel like to experience the strong winds of a hurricane. The powerful, fast-moving, line of thunderstorms known as a derecho, blasted across Iowa Aug. 10 with extreme winds. The derecho did catastrophic damage to corn and soybean crops, caused widespread utility and property damage, and resulted in fatalities. NOAA estimates damage totals to be $7.5 billion, making it one of the most costly severe thunderstorm events in U.S. history...
September 15, 2020
This diagram illustrates the processes occurring within hailstorms, and how satellites observe these storms and the damage they cause to the land surface. Credit: NASA
As a child, Kristopher Bedka was fascinated with weather extremes. He grew up in Chicago and always wanted to experience the maximum that the atmosphere had to offer. “When it was forecasted to be cold, I always wanted to see and feel what record cold and snow were like. I wanted us to have two feet of snow instead of two inches. When a severe storm warning was issued, I always stared out the window wanting to see the worst of the storm.” In high school he was given a survey that asked him to choose what he wanted to be when he grew up, and among all of the options meteorologist stood out to...
September 10, 2020
GOES imagery of a hailstorm
When a hail storm strikes, the damage can be catastrophic for homes, businesses, agriculture and infrastructure. In fact, with damage totals sometimes exceeding $1 billion, hailstorms are the costliest severe storm hazard for the insurance industry, making reliable, long-term data necessary to estimate insured damage and assess extreme loss risks. Video of Hailstorm near Burkburnett, Texas A Geostationary Operational Environmental Satellite–16 (GOES-16) animation of color-enhanced infrared wavelength temperature overlaid upon visible wavelength brightness imagery from May 22-23,...
August 21, 2020
The Operational Land Imager (OLI) on Landsat 8 captured an image of storm-damaged fields around Marshalltown, Iowa, on August 11th, 2020. Credit: NASA Earth Observatory
Despite facing a dry July, many farmers in Iowa were expecting a good harvest in the fall. Instead, many had their fields of corn and soybeans flattened by hurricane-force winds. On August 10, 2020, an unusually strong and long-lasting line of thunderstorms—a derecho—battered vast swaths of Iowa and the U.S. Midwest. More than a week after the storm, tens of thousands of Iowans were still without electric power, and many farmers were mulling whether they could salvage crops and repair grain silos before the coming harvest.
January 5, 2018
Animated image of storm
GPM Image captured 5:44 UTC (12:44am EST) The GPM core satellite captured this first image of the storm at 5:44 UTC (12:44 am EST) Thursday January 4th, 2018 as the surface low was passing off Cape Hatteras, North Carolina. The image shows DPR (radar) surface precipitation rates in the center of the swath and GMI (microwave) rates in the outer swath overlaid on enhanced IR data from GOES-East. The DPR swath passed just northeast of the...
August 15, 2016
NASA Analyzes Deadly Louisiana Flooding
Record-setting rainfall and flooding in southern Louisiana have been calculated at NASA with data from satellites. An extremely severe rainfall event hit the states of Louisiana and southern  Mississippi when a very slow moving low pressure system continuously pulled tropical moisture from the Gulf of Mexico. NASA's IMERG data from Aug. 8 to Aug. 15, 2016 showed over 20 inches (508 mm) of rainfall was estimated in large areas of southeastern Louisiana and extreme...