Fri Aug 27, 2004
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Hail Alley, next on The Weather Notebook.
Tornado Alley is a popular term in the American weather lexicon, but did you know there is a Hail Alley too? Hi, I’m Bryan Yeaton for The Weather Notebook.
Hail Alley sits east of the Rockies, in the area where Colorado, Nebraska, and Wyoming meet. It can extend into Montana, South Dakota and Kansas, all on the High Plains, then southward through Oklahoma and north Texas.
Some locations here get twenty or more hailstorms each year, most between May and June, although the season extends from April to October.
Lying east of the Laramie Mountain Range, Cheyenne, Wyoming has the distinction of being North America’s most hail-prone city, with an average of nine to ten hailstorms per season.
Central Oklahoma receives North America’s highest frequency of large hail, stones at least 3/4-inches in diameter, with eight to nine events annually. Residents along Colorado’s Front Range can usually expect three or four catastrophic hailstorms, which cause at least $25 million in insured damage, every year.
The climatology of hail events where stones are greater than 2 inches in diameter, shows the area most at risk is the High Plains stretching from North Dakota to Texas with greatest frequency in central Oklahoma and north central Texas. Such severe hailstorms occur in the southern Plains early in the thunderstorm season, then migrate northward to the Central and Northern Plains in late spring and summer.
There are also hail alleys in northern India and western Canada. The Canadian Hail Alley sits in Alberta east of the Rocky Mountains. A common thread between the three regions appears to be a mid latitude location on the downwind side of a large mountain chain.
Thanks to our contributing writer, meteorologist Keith Heidorn. The Weather Notebook receives support from Subaru of America and the National Science Foundation.
Severe Thunderstorm Climatology