Tornadoes & Water Spouts

A tornado is defined as a violently rotating column of air extending from a thunderstorm to the ground. The most violent tornadoes are capable of tremendous destruction with wind speeds of 200 mph or more.

In an average year, 800 tornadoes are reported nationwide, resulting in 80 deaths and over 1,500 injuries. Florida is #3 in number of tornadoes. Most are weak. However, strong ones do occur. Tornadoes are classified by intensity and damage on the Fujita Scale similar to the Saffir-Simpson Hurricane Scale.

The Fujita Scale

Category	Wind Speed (MPH)	Intensity
F0	< 73	Gale
F1	73-112	Moderate
F2	113-157	Significant
F3	158-206	Severe
F4	207-260	Devastating
F5	261-318	Incredible

Weak Tornadoes	Strong Tornadoes	Violent Tornadoes
69% of tornadoes	29% of tornadoes	Only 2% of tornadoes
< 5% of tornado deaths	30% of tornado deaths	70% of tornado deaths
Lifetime 1-10+ minutes	Lifetime: 20 min or longer	Lifetime can exceed 1 hour
Winds < 110 mph	Winds 110-205 mph	Winds > 205 mph

Tornado Myths & Facts

MYTH: Areas near rivers, lakes and mountains are safe from tornadoes.
FACT: No place is safe from tornadoes. In the late 1980's, a tornado swept through Yellowstone National Park leaving a path of destruction on a 10,000 foot mountain.

MYTH: The low pressure in a tornado causes buildings to "explode" as the tornado passed overhead.
FACT: Violent winds and debris slamming into buildings cause most structural damage.

MYTH: Windows should be opened before a tornado approaches to equalize pressure and minimize damage.
FACT: Opening windows allows damaging winds to enter the structure. Leave the windows alone. Instead, immediately go to a safe room.

When a tornado threatens:

Know the terms used to describe tornado threats:

Tornado Watch - Tornadoes are possible. Remain alert for approaching storms. Listen to your battery-operated NOAA Weather Radio or local radio/television outlets for updated reports.
Tornado Warning - A tornado has been sighted or indicated by weather radar. Take shelter immediately.

Purchase a NOAA Weather Radio with a battery backup and tone-alert feature that automatically alerts you when a Watch or Warning is issued (tone alert not available in all areas). Purchase a battery-powered commercial radio and extra batteries as well.

For additional safety information and planning guidance, refer to the Tornado Safety Checklist, Checklist 8 in Appendix in the Guidebook or on the checklist page of this site.