(Updated 29 March 2013. Comments to Harold
At NOAA's National Severe Storms Laboratory,
we have begun a project to estimate the likelihood of severe weather hazards
in the United States. (Severe thunderstorms are defined in the United
States as having either tornadoes, gusts at least 58 mph, or hail
at least 3/4 inch in diameter.) The figures are of three primary
For more information on the raw data that went into the figures and how
it was processed, click here.
The average number of days per year with the event occurring within 25
miles of any point (Total Threat).
Animated loops of the probability of severe weather occurring within 25
miles of any point on a particular day with images once per week through
the year (Animated Loops).
Graphs showing the annual cycle of the probability of severe weather occurring
within 25 miles at any point you select (Annual
Cycles at Points [Clickable Maps]).
Conference paper on climatology
of strong and violent tornadoes in the US by Concannon, Brooks,