National Weather Service United States Department of Commerce

Tornado Infographics


Tornado Sheltering Guidelines: Seek the best available refuge area immediately when a Tornado Warning is issued. Your chance of surviving a tornado is excellent if you follow these guidelines. BEST OPTIONS: 1)Above or below ground Tornado Storm Shelter (NSSA/ICC 500 compliant). 2)Specifically-designed FEMA Safe Room. FEMA recommends either of these options. GOOD OPTIONS: 1)Interior room of a well-constructed home or building. 2)Basement. BAD OPTIONS: 1)Large open rooms like gymnasiums. 2)Manufactured housing. WORST OPTIONS: 1)Mobile homes. 2)Vehicles. 3)Underneath a highway overpass.
TORNADO TERMINOLOGY 1) Tornado Watch: Weather conditions could lead to the formation of severe storms and tornadoes. Be prepared! Know your safe location. Be ready to act quickly if a Warning is issued or you suspect a tornado is approaching. 2) Tornado Warning: A tornado has been spotted or indicated by weather radar, meaning a tornado is occurring or expected soon. Take Action! There is imminent danger to life and property. Immediately seek refuge in the safest location possible. 3) Tornado Emergency: An exceeding rare situation with a severe threat to human life and catastrophic damage due to a confirmed violent tornado. Take Action! Immediately seek refuge in the safest location possible.
Have you ever noticed the wording THIS IS A PARTICULARLY DANGEROUS SITUATION in some of the severe weather watches issued by the NWS Storm Prediction Center? This wording is used in Tornado Watches for rare situations when long-lived and intense tornadoes are likely. This enhanced wording my also accompany Severe Thunderstorm Watches for widespread and exceptionally intense straight-line wind events. BE PREPARED: Review your severe weather safety procedures. Know the safest place to seek refuge ahead of time. Consider canceling or postponing outdoor activities. Have multiple ways to receive a warning. Inform others of the heightened risk.
TORNADOES AND ROAD SAFETY. 1) What To Do: Get off the road. The best option is to drive to a designated shelter, basement or safe room. The next best option is a small, windowless room or hallway on the lowest floor of a sturdy building. 2) What No To Do: Do not seek refuge in a vehicle, outside or under an overpass. A highway overpass does not provide safety from a tornado. Do not seek shelter under an overpass or a tree. This puts you at greater risk of being killed or seriously injured by flying debris from the powerful tornadic winds.
Supercell Tornadoes:
Tornadoes that come from a supercell thunderstorm are the most common, and often the most dangerous. A rotating updraft is a key to the development of a supercell, and eventually a tornado. There are many ideas about how this rotation begins. One way a column of air can begin to rotate is from wind shear – when winds at two different levels above the ground blow at different speeds or in different directions. Once the updraft is rotating and being fed by warm, moist air flowing in at ground level, a tornado can form.

Landspouts, narrow, rope-like condensation funnels that form while the thunderstorm cloud is still growing and there is no rotating updraft. The spinning motion originates near the ground.

Waterspouts, similar to landspouts, except they occur over water.

Gustnadoes, whirls of dust or debris at or near the ground with no condensation funnel, which form along the gust front of a storm.

Dust Devils:
A well-developed dust whirl; usually of short duration, rendered visible by dust, sand, and debris picked up from the ground. Dust devils are best developed on a hot, calm afternoon with clear skies, when intense surface heating causes large temperature differences in the lowest couple hundred feet of the atmosphere.

Fire Whirls:
Much like dust devils, the extreme heat of fires create strong updrafts, near the ground that interact with circulations in the lower atmosphere. Fire whirls are usually about 1 to 3 feet  wide and 50 to 100 feet tall.
Enhanced Fujita Scale for Tornadoes - Six Damage Categories:
EFO - Wind: 65-85 mph / Damage: minor
EF1 - Wind: 86-110 mph / Damage: moderate
EF2 - Wind: 111-135 mph / Damage: considerable
EF3 - Wind: 136-165 mph / Damage: severe
EF4 - Wind: 166-200 mph / Damage: devastating
EF5 - Wind: 200+ mph / Damage: incredible
Know Where to Go When Sheltering from a Tornado:
Quickly move to your basement and bring your emergency supply kit. If you have no basement, move to an interior room with no windows. Top floor rooms do not protect you. Exterior rooms and rooms with windows do not protect you. No place outside is safe from a tornado.
2011 Tornado Outbreaks - timeline of events:
#1 April 4-5: Midwest/Southeast Tornadoes and Straight-Line Winds (KS, MO, IA, IL, WI, KY, GA, TN, NC, SC) - 46 tornadoes / Total costs: $3.0 Billion; 1 Death
#2 April 8-11: Southeast/Midwest/Plains Tornadoes (NC, SC, TN, AL, TX, OK, KS, IA, WI) - 50 tornadoes / Total costs: $2.3 Billion; 0 Deaths
#3 April 14-16: Plains/Midwest/Southeast Tornadoes (OK, TX, AR, MS, AL, GA, NC, SC, VA, PA) - 178 tornadoes / Total costs: $2.2 Billion; 38 Deaths
#4 April 19-24: Ohio Valley/South Tornadoes and Straight-Line Winds (AR, IL, IN, KY, MO, OH, TN, TX) - 130 tornadoes / Total costs: $1.1 Billion; 0 Deaths
#5 April 25-28: Southeast/Ohio Valley/Midwest/Plains Tornadoes (AL, AR, LA, MS, GA, TN, VA, KY, IL, MO, OH, TX, OK) - 349 tornadoes / Total costs: $10.8 Billion; 324 Deaths
#6 May 22-27: Plains/Midwest/Southeast Tornadoes (MO, TX, OK, KS, AR, GA, TN, VA, KY, IN, IL, OH, WI, MN, PA) - 226 tornadoes / Total costs: $9.6 Billion; 177 Deaths
Tornado Safety for your apartment:
For an apartment or university dormitory, go to the lowest possible floor and into a central room. Crouch under an indoor stairwell or in an interior windowless hallway. Cover your head and neck to protect yourself from falling debris.
Tornado Safety for your home:
Move to the lowest level and to an interior room without windows, like a closet or bathroom. If you have a basement in your home, this is your best option. Cover your head and neck to protect yourself from falling debris.
What to do during a tornado watch:
When a Tornado Watch is issued, make sure the following items are stored in your safe place:
 - Helmets, pillows, or even a mattress to protect your head from falling and flying debris
 - Shoes to protect your feet from broken glass and other sharp objects
 - A whistle or noise-making device to signal for help after the storm passes
 - Baby formula, diapers, and other necessary items for your children
 - Pet carriers, leashes, and other pet supplies