Hail is formed in what kind of cloud

From the legend, we can see that some areas average less than one day of hail per year, whereas others average more than Frequencies are low on the Pacific Coast, where contrasts between air masses are typically weak. Frequencies are also low in most of the interior of the West, which is typified by relatively dry air. Frequencies are slightly higher in a north-south band through Arizona , which experiences thunderstorms during a summer monsoon. Hail occurs most frequently over the Great Plains, in the center of the map, in a wide, north-south band stretching from central Texas to the Canadian border and beyond.

The average size of hailstones is larger over the Great Plains than anywhere else in the U. Most damage from hail is from larger hailstones e. Frequencies in the eastern U. The size of hailstones generally becomes smaller toward the coast. Florida and areas along the Gulf Coast have frequent thunderstorms, but low to intermediate frequencies of hail. Here, thunderstorms are seldom tall enough and well-organized enough to form hail. Furthermore, temperature contrasts between air masses is usually not as great as over the Great Plains.

The four maps below show hail frequencies for four different months, each representative of a season winter, spring, summer, and fall, from left to right. How does hail vary from season to season?

Hail is most frequent in the spring and summer e. In spring, the surface warms more rapidly than the overlying air, which must be heated by the surface itself. Successively higher locations in the atmosphere require longer to heat. This sets up a steep environmental lapse rate, in which the surface can be quite warm while the atmosphere is cold.

This destabilizes the atmosphere, setting the stage for the cumulonimbus clouds that are required for hail to form. In fall, the pattern is reversed as the surface cools more rapidly than the air above it, and the atmosphere is seldom so unstable.

Once situated on the upper part of the cloud, the hailstone falls down and is lifted again. Each time the hailstone goes through an area with a lot of supercooled water, it grows in size and increases in weight.

Once it becomes too heavy, the hailstone is either ejected from the top of the cloud because of the intertia or falls from the bottom because of gravity. Hail is destructive to cars, crops, greenhouses, etc… But the largest hailstones are dangerous not only for fixed objects but also to human and animal life. In very rare cases, hail storms have killed both animal and people. The most destructive hail storms typically occured in high altitude, montainous regions such as Northern India, Bangladesh, Mexico, Argentina and various parts of the USA and Canada.

In many cases, ice pellets are smaller than hailstones but this kind of precipitation can also cause damages. Explore these resources to teach your students about catastrophic weather events and how they impact every part of the world.

The environmental hazards you face depend on where you live. For example, if you live in northern California you are more likely to be impacted by a wildfire, landslide, or earthquake than if you live in Charleston, South Carolina, but less likely to be hit by a hurricane.

This is because the physical conditions in each place are different. The active San Andreas fault runs through California and causes regular earthquakes, while the warm waters transported by the Gulf Stream can intensify a storm heading for South Carolina. These environmental hazards shape human activity regionally. Learn more about environmental hazards with this curated resource collection. Toss supercooled water into an updraft of air within a thundercloud and what do you get?

A hailstorm! Cloud cover is an important component of understanding and predicting the weather. Not only does cloud cover impact sky conditions and inform precipitation predictions, it also helps regulate the temperature that occurs in a region. Join our community of educators and receive the latest information on National Geographic's resources for you and your students.

Skip to content. Twitter Facebook Pinterest Google Classroom. Encyclopedic Entry Vocabulary. Hail can be transparent clear or translucent cloudy. Great Plains. Hail Alley. Media Credits The audio, illustrations, photos, and videos are credited beneath the media asset, except for promotional images, which generally link to another page that contains the media credit.

Last Updated Jan. Media If a media asset is downloadable, a download button appears in the corner of the media viewer. Text Text on this page is printable and can be used according to our Terms of Service. Interactives Any interactives on this page can only be played while you are visiting our website. Related Resources. View Collection. Catastrophic Weather Events. Environmental Hazards.