LITTLE ROCK, Ark. (AP) — Strong storms including at least one tornado were moving through the Ohio River Valley on Tuesday, a day after about two dozen tornadoes were reported across the Plains, including deadly twisters that destroyed homes and overturned vehicles in Oklahoma.
Tornadoes are relatively common this time of year in parts of the central U.S., though the storms can strike in other locations and seasons if conditions are right. Here is some information about the nation's tornado history and tips on staying safe:
Advances in science and communications have lengthened warning times over the years, but even then the wrong storm at the wrong place can kill dozens or even hundreds.
The nation's worst tornado outbreak was only five years ago, on April 27-28, 2011, when 175 tornadoes killed 316 in Alabama, Georgia, Mississippi, Tennessee and Virginia. That series of storms surpassed those of April 3-4, 1974, when 127 tornadoes killed 310, mostly in the Ohio Valley.
The Tri-State tornado of March 18, 1925, killed 695 people in Missouri, Illinois and Indiana, and since then the highest death toll from a single storm is 158 at Joplin, Missouri, on May 22, 2011.
WHO'S MOST AT RISK?
The nation's midsection and the Southeast see the most storms, but some forecasters don't like the term Tornado Alley because they prefer to make the point that storms can form anywhere. Tornadoes have been reported in every state, including Alaska.
Storm Prediction Center data compiled in 2010 showed that, in the previous 30 years, Texas had the most storms, followed by Kansas, Florida and Oklahoma. (Alaska had three.) Texas had the greatest number of killer tornadoes, too, followed by Arkansas, Tennessee and Missouri.
Among cities, more have occurred in Oklahoma City than anywhere else — more than 100 since 1893.
BIG AND STRONG
A twister 2.6 miles wide struck near El Reno, Oklahoma, on May 31, 2013, with winds measured at 290 mph about 500 feet above the ground. It was a bit larger than a tornado that hit Hallam, Nebraska, on May 22, 2004.
A May 3, 1999, storm that later killed 36 people at Moore, Oklahoma, had winds of about 302 mph at Bridge Creek, Oklahoma.
The wind speeds in these storms were measured using Doppler radar rather than traditional anemometers, which can be swept away when directly hit by a storm.
HOW TO STAY SAFE?
It's all about having a plan, and start planning early if possible.
To begin, buy a weather radio, which carries alerts from your local National Weather Service office (and many models can be programmed to sound an alert tone only if your area is threatened.) You should also clear a path to your basement or a closet or interior room on the lowest floor of your home. The golden rule: Put as many walls between you and the outside.
On the day of the storm, tune in to local broadcasters or your local NWS office and follow them and FEMA on social media if you will check it often enough. Avoid media that won't automatically cut in with warnings for your area.
A watch means conditions are good for storms to develop. The National Weather Service says it means just that: Watch.
If you are home when a warning is issued, go to your safe place. You have been warned. Remember — as many walls as possible between you and the outside. Don't go outside to confirm the storm is in your area. Spotters and forecasters have already done that.
If you are in car when a warning is issued, flee if it is safe to do so, but be aware thousands of others may have the same idea. If you are unable to get away, get out of your vehicle and into the lowest place possible (but watch for areas prone to flash flooding). Do not go under a bridge, where winds can actually be higher because of a change in air pressure where it passes beneath.
Source: Storm Prediction Center, National Weather Service.