What is a severe thunderstorm? We continue our Severe Weather Preparedness Week coverage with a look at Severe Thunderstorms.

The National Weather Service has established the threshold characterizing a severe thunderstorm as a storm that produces hail 3/4 of an inch or greater and/or winds of around 60mph or greater. Severe thunderstorms are also known to produce flooding rains, frequent cloud to ground lightning, and even tornadoes.

Severe Thunderstorm Watch: Severe T-Storms possible within a period of several hours. Be prepared to take action should a severe thunderstorm develop.

Severe Thunderstorm Warning: A severe thunderstorm capable of producing gusty winds and/or large hail has been sighted or detected by Doppler Radar, and is threatening to cause property damage and/or injury. GO INDOORS IMMEDIATELY AND STAY AWAY FROM WINDOWS!

Damaging straight-line or downburst winds from thunderstorms can do as much if not more damage to property as a weak or moderate tornado, as we know very well here in the City of Rockford. Take the July 5, 2003 storm for example. That's the one that took down our broadcast tower here at 23 WIFR, and caused more than 100,000 power outages, and millions of dollars in damages. This underscores the need to take severe thunderstorm warnings very seriously.

According to the NWS, very large hail, golf ball sized or larger, is not only very destructive, but it occurs with the most violent of storms.