Recently, an outbreak of severe weather swept across several southern states, producing a number of tornadoes, including one in Mississippi that has been responsible, so far, for 26 dead, dozens injured, and number of missing.
If I had to choose between being in the path of a hurricane or a tornado, I’d prefer the hurricane. Why? Because hurricanes are predictable these days, so you get to prepare for them. Tornadoes? Well, not so much. It’s the element of surprise that leads to hundreds killed and injured by these storms annually. Knowing what to do before a tornado touches ground helps avoid many tragic outcomes.
A tornado (also called a “twister”) is a violently rotating column of air that is in contact with both the surface of the earth and the thunderstorm (sometimes called a “supercell”) that spawned it. From a distance, tornadoes appear in the form of a visible dark funnel with all sorts of flying debris in and around it. They may be difficult to see up close due to accompanying rainfall.
Tornado alley image by Tertius51, CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0>, via Wikimedia Commons
Almost a thousand tornadoes touch ground in the United States every year, more than are reported in any other country. Most of these occur in “Tornado Alley,” an area that isn’t officially defined but encompasses the land between the Rocky and Appalachian Mountains. Peak tornado season in the southern U.S. states is March through May; in the northern states, it’s late spring through early summer. Some believe that Tornado Alley is shifting east over the years.
In the United States, tornadoes average 500 feet (150 meters) across and travel on the ground for about 5 miles (8.0 kilometers). Tornadoes may generate winds of up to 300 miles per hour and be accompanied by hail.
While in contact with the ground, twisters can travel at a speed of 30 miles (48 kilometers) per hour. Others may “hop” from point to point before petering out. Those in close proximity to the funnel will note a roaring sound that’s reminiscent of a passing train.
(Aside: Having personally experienced this decades ago, we can confirm that it’s terrifying.)
Injuries from tornadoes are usually due to trauma from flying debris carried by the winds. In some cases, very large objects are flung around in a manner that is hard to believe. Indeed, there’s a report from 1931 that an 83-ton train was lifted and thrown 80 feet from the tracks.
There are various classification models for tornadoes, but the most commonly used is the Enhanced Fujita Scale. Fujita levels are rated from 0-5, based on wind speeds and the amount of damage caused:
F0 Light: Winds 65-85 miles per hour; smaller trees uprooted or branches broken, mild structural damage.
F1 Moderate: winds 86-110 miles per hour; broken windows, small tree trunks snapped, overturned mobile homes, destruction of carports or toolsheds, roof tiles missing (this is the level that struck our home).
F2 Considerable: winds 112-135 miles per hour; mobile homes destroyed, major structural damage to frame homes due to flying debris, some large trees snapped in half or uprooted.
F3 Severe: winds 136-165 miles per hour; roofs torn from homes, small frame homes destroyed, most trees snapped and uprooted.
F4 Devastating: winds 166-200 miles per hour; strong-structure buildings damaged, destroyed or lifted from foundations, cars lifted and blown away, large debris becomes airborne (The worst of the Mississippi tornadoes was given this level).
F5 Incredible: winds greater than 200 miles per hour; larger buildings lifted from foundations, trees snapped, uprooted, and debarked, objects weighing more than a ton become airborne missiles.
Although some places may have sirens or other methods to warn you of an approaching twister, every family should have a plan of action before a tornado appears. Children should know where to find medical kits and how to use a fire extinguisher. If appropriate, teach everyone how to safely turn off the gas and electricity.
When you are in the path of a tornado, take shelter immediately unless you live in a mobile home. These are especially vulnerable to damage from the winds. If there is time, get to the nearest building that has a tornado shelter; underground shelters are best.
If you live in Tornado Alley, you might consider putting together your own underground shelter. Unlike bunkers and other structures built for long-term use, a tornado shelter only has to provide safety for a short period of time. As such, it doesn’t have to be very large: 8-10 square feet per person would be acceptable. Despite this, be sure to consider ventilation and the comfort or special needs of potential occupants.
Tornado shelter or “storm cellar”
If you don’t have a shelter, find the safest place in the house where family members can gather. Basements, bathrooms, closets, or inside rooms without windows are the best options. Windows can easily shatter due to impact from flying debris.
Speaking of windows, some suggest opening windows due to the great pressure caused by a tornado. Well, most windows are made of ¼ inch panes of glass, and you’re not going to prevent your roof from being blown off simply by opening them. It’s the speed and violence of the winds, not the pressure, that causes the most damage to homes.
For added protection, get under a heavy object such as a sturdy table. Covering your body with a sleeping bag or mattress will provide an additional shield. Discuss this plan of action with every member of your family until it’s clear they will know this process by heart.
If you’re in a car and can drive to a shelter, do so. Although you may be hesitant to leave your vehicle, remember that they can be easily tossed around by high winds; you may be safer in a culvert, ditch, or other area lower than the roadway. It is not safe, however, to hide under a bridge or overpass, as the winds can easily reach you.
In town, leaving the car to enter a sturdy building is appropriate. If there is no other shelter, however, staying in your car will protect you from some of the flying debris. Keep your seat belt on, put your head down below the level of the windows, and cover yourself as much as possible.
If you’re out hiking when the tornado hits, get away from heavily wooded areas. Torn branches and other debris become missiles, so an open field or ditch may be safer. Lying down flat in a ditch or other low spot in the ground will give you some protection. Make sure to cover your head, if at all possible, even if it’s just with your hands.
One final bit of advice: If you have pets, make provisions for them in your emergency plan. Your local disaster shelter may not have supplies for them.
Joe Alton MD
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