National Weather Service United States Department of Commerce
News Headlines
Hazard Map Threat Levels Safety & Impact
Graphical Hazardous Weather Outlook
Severe Hail Threat

The "Severe Hail Hazard Map" depicts the local threat of severe hail for specified areas.  It is based on the likelihood that severe hail will occur combined with the anticipated size (diameter) of the biggest stones.

Severe Hail Threat Level

Threat Level Descriptions

Extreme

"An Extreme Threat to Life and Property from Severe Hail."

Within 12 miles of a location, a moderate likelihood or greater (16% probability or greater) of severe hail, with storms capable of baseball to softball sized stones.  See diameter description below.

AND/OR...a  high likelihood or greater (26% probability or greater) of severe hail, with storms capable of golf ball to baseball sized hail stones.  See diameter description below.

AND/OR...a  very high likelihood (36% or greater) of severe hail, with storms capable of nickel to golf ball sized hail stones.  See diameter description below.

High

"A High Threat to Life and Property from Severe Hail."

Within 12 miles of a location, a low likelihood (6% to 15% probability) of severe hail, with storms capable of baseball to softball sized stones.  See diameter description below.

AND/OR...a moderate likelihood (16% to 25% probability) of very large hail (golf ball to baseball sized hail stones).  See diameter description below.

AND/OR...a high likelihood (26% to 35% probability) of large hail (nickel to golf ball sized hail stones).  See diameter description below.

Moderate

"A Moderate Threat to Life and Property from Severe Hail."

Within 12 miles of a location, a very low likelihood (2% to 5% probability) of severe hail, with storms capable of baseball to softball sized stones.  See description below.

AND/OR...a low likelihood (6% to 15% probability) of severe hail, with storms capable of golf ball to baseball sized hail stones.  See description below.

AND/OR...a moderate likelihood (16% to 25% probability) of severe hail, with storms capable of nickel to golf ball sized hail stones.  See diameter description below.

Low

"A Low Threat to Life and Property from Severe Hail."

Within 12 miles of a location, a very low likelihood (2% to 5% probability) of severe hail, with storms capable of golf ball to baseball sized hail stones.  See diameter description below.

AND/OR...a low likelihood (6% to 15% probability) of severe hail, with storms capable of nickel to golf ball sized hail stones.  See diameter description below.

Very Low
" A Very Low Threat to Life and Property from Severe Hail."

Within 12 miles of a location, a very low likelihood (2% to 5% probability) of severe hail, with storms capable of nickel to golf ball sized hail stones.  See diameter description below.

AND/OR...a low likelihood or greater (6% or greater) of small hail (less than 3/4 inch).  See diameter description below.

Non-Threatening
" No Discernable Threat to Life and Property from Severe Hail."

Within 12 miles of a location, environmental conditions do not support the occurrence of severe hail.     

Note: To be considered severe, hail stones must be at least 3/4 inch in diameter.

Small Hail - Hail less than 3/4 inch in diameter (from the size of peas to marbles).

Large Hail - Hail from 3/4 inch to 1 3/4 inch in diameter (from the size of nickels to golf balls) causing minor damage. 

Very Large Hail  - Hail from 1 3/4 inch to 2 3/4 inch in diameter (from the size of golfballs to baseballs) causing moderate damage. 

Giant Hail - Hail larger than 2 3/4 inch (larger than baseballs, such as the size of grapefruit or softballs) causing major damage. 

Determining Likelihood