Includes Puerto Rico and the U. Virgin Islands. Subject to change as loss estimates are further developed. As of February 23, A tornado that crosses state lines is counted as a single event in this chart.
View Archived Graphs The following chart shows the top 10 catastrophes involving tornadoes. It counts severe convective storms that may include tornadoes and other perils such as straight-line winds derechos and hail. The August 10, , Midwest Derecho, which is included in the chart as part of the August , outbreak, would rank as the fourth-costliest insured severe convective storm event on record for the U. Includes events that occurred through Consumer Price Index.
View Archived Tables The costliest U. Tornadoes, however, are much more likely during the day, especially during the late afternoon and early evening, not at night.
Tornadoes are also much more common in the spring than in the summer in most parts of the country. Bluestein: During PECAN, scientists and students are using a large group of instruments to take measurements in the atmosphere before and during nocturnal thunderstorms. Some instruments are being driven to areas in the Plains where storms are expected to form, and others are flown to these areas on aircraft.
Analyses of the vast amounts of data collected, and the use of state-of-the-art computer models, will shed light on how nocturnal storms form. Bluestein: The instruments include sophisticated Doppler radars, lasers and devices that measure radiation, which can tell us what the temperature and humidity are. Other more conventional instruments such as thermometers and anemometers are mounted on the roofs of cars.
Weather balloons are also being launched from mobile platforms. Bluestein: Nocturnal thunderstorms that occur in large complexes or lines are capable of producing damaging winds, hail and torrential rainfall that can result in flash flooding. Tornadoes, however, while possible, occur much less frequently at night. Lightning is also a significant hazard.
Bluestein: Be sure to secure all outdoor patio furniture and other things that can be blown around by strong winds. Park cars in garages or under shelters if possible to protect them from hail or falling tree branches. Usually created by surface heating, convection is upward atmospheric motion that transports whatever is in the air along with it—especially any moisture available in the air.
A thunderstorm is the result of convection. What is a severe thunderstorm? How many thunderstorms are there? Worldwide, there are an estimated 16 million thunderstorms each year, and at any given moment, there are roughly 2, thunderstorms in progress. There are about , thunderstorms each year in the U.
When are thunderstorms most likely? Thunderstorms are most likely in the spring and summer months and during the afternoon and evening hours, but they can occur year-round and at all hours. Along the Gulf Coast and across the southeastern and western states, most thunderstorms occur during the afternoon. Thunderstorms frequently occur in the late afternoon and at night in the Plains states. What kinds of damage can thunderstorms cause?
Light waves travel so rapidly that lightning is seen instantly. Sound waves travel much more slowly, so a thunderclap may come many seconds after the lightning is spotted. Thunderstorms kill approximately people in the United States and injure about Americans per year, mostly from lightning strikes.
Skip to main content. Weather Processes and Systems. Search for:. Thunderstorms Weather happens every day, but only some days have storms. Thunderstorm Genesis All thunderstorms go through a three-stage life cycle. Licenses and Attributions.
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