This cumulonimbus cloud has the characteristic anvil-shaped top.
Click on image for full size
Courtesy of UCAR Digital Image Library

Thunderstorms

Thunderstorms are one of the most exciting and dangerous types of weather. Over 40,000 thunderstorms happen around the world each day.

Thunderstorms form when very warm, moist air rises into cold air. As this air rises, water vapor condenses and forms huge cumulonimbus clouds.

There are two main types of thunderstorms: ordinary and severe. Ordinary thunderstorms usually last about one hour and can produce rain and small hail.

Severe thunderstorms are very dangerous. They can produce baseball-sized hail, strong winds, intense rain, flash floods, and tornadoes. Severe thunderstorms can last several hours.

Last modified May 27, 2010 by Becca Hatheway.

You might also be interested in:

Cool It! Game

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

Condensation

Condensation is when water changes its state from a vapor or gas to a liquid. Condensation is responsible for the formation of clouds. Common examples of condensation are: dew forming on grass in the early...more

Cumulonimbus

Cumulonimbus clouds belong to the Clouds with Vertical Growth group. They are also known as thunderstorm clouds. A cumulonimbus cloud can grow up to 10km high. At this height, high winds make the top...more

Rain

Raindrops form when tiny water droplets collide together in clouds to form bigger ones. When they get too heavy, rain falls out of the clouds. Rain is more than 5mm in diameter. The types of clouds that...more

Supercell Thunderstorms and Squall Lines

A supercell thunderstorm is a huge rotating thunderstorm. It can last for several hours. These storms are likely to form long lasting tornadoes and large hail. There are two types of supercell thunderstorms....more

Wind

Wind is moving air. Warm air rises, and cool air comes in to take its place. This movement creates the winds around the globe. Winds move at different speeds and have different names based on their speed....more

Forecasting Flash Floods in Colorado's Mountains

Dangerous flash floods have killed hundreds of people and caused lots of damage to buildings and roads in the Front Range of Colorado’s Rocky Mountains. The area gets summer flash floods because of its...more

Small Satellite Takes on Large Thunderstorms

Scientists and students have designed a new satellite called Firefly. This satellite is the size of a loaf of bread and is designed to help solve the mystery of terrestrial gamma-ray flashes (TGFs). TGFs...more

Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA