A. Geography

Global

Hails can occur anywhere in the world where convective storms occur. Near mountainous terrain, the additional uplift often increases hail occurrences. Some of the highest frequencies of hail occur in western China and northern India. Hail also occurs frequently near the Alps in Europe, Andes in S. America, and in mountainous east Africa. Australia also has hail, particularly in New South Wales. For information on Australian hail, see: http://www.boin.gov.au/weather/nsw/sevwx/hailfact.shtml and http://www.nssl.noaa.gov/swat/990414/case.html for the 1999 Sidney, Australia hailstorm. The climatology of hailstorms in Great Britain may be seen at: http://www.torro.org .

North America

In the United States, hails most frequently occur in Hail Alley: The Great Plains states, especially northeastern Colorado and southeastern Wyoming, receive more hail yearly than any other part of the United States. The states experiencing the most frequent hail include: Colorado, Wyoming, Nebraska, Kansas, Texas, and Oklahoma. Hail in this area of the country is most likely to fall late in the afternoon during the months of May and June and is often responsible for extensive crop loss, property damage and livestock deaths. While hail is most frequent in NE Colorado, severe hail (3/4” or greater, or damaging) shows highest frequencies further east, in Oklahoma.

Geography of large hail

Large hail is known to farmers and insurance companies as the most destructive. In the map below, hail of 2” and greater is mapped.

(source: NSSL, NOAA)

To look for hail occurrences in any state of the United States, please go to http://www.nssl.noaa.gov/hazard/hazardmap.html

A map of severe hail in Colorado shows that not all of the state has high risk for damaging hail. However, of the 1200 reported events, clusters appear in NE Colorado over the High Plains parallel to the Rocky Mountains.

Distribution of severe hail in Colorado. (source:http://ccc.atmos.colostate.edu/~hail/pdfs/Hail%20_Hazard.pdf)

For more information on Colorado hail, please go to

http://www.waterknowledge.colostate.edu/hail.htm and

http://www.crh.noaa.gov/pub/hail&tor_co.html

The Kentucky hailstorm of 1998 is discussed at:

http://kyclim.wku.edu/BRADD/hail/1998.html

Canadian hailstorms occur most frequently to the east of the Rockies in Alberta, with damaging hail also occurring along the southern portions of the Prairie Provinces, Ontario and Quebec.

For information on hailstorm patterns in Alberta using radar, see:

http://datalib.library.ualberta.ca/AHParchive/radar-biblio.html

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