As we continue to experience stronger and more destructive tornado and straight-line wind events, more safety information emerges from studying them. But the primary message has remained the same: 'Get as low as you can, and put as many walls as you can between you and the tornado'. The below article, written by Harold Brooks, a meteorologist whose research focuses on severe convective weather and climatology, gives a great summary of why this safety message has stood the test of time.
At the heart of it, this single sentence summarizes most of tornado safety advice. Although there are special situations that require additional information, if someone in the path of a tornado follows this advice, their chances of survival dramatically increase. For the most part, the partnership between the National Weather Service, the media, and emergency management personnel emphasizes this same message. The words may differ (lowest floor, interior room, bathroom or closet), but the core idea remains the same. Obviously, having a purpose-built shelter is ideal, but not everyone has one.
Occasionally, someone strays from this basic messaging, potentially causing problems. Many in the tornado safety community are concerned about an inappropriate message that seems to have become very popular recently, but that differs significantly from the basic safety idea. Some broadcast meteorologists have offered the advice that “if you don’t get underground, you won’t survive.” Sometimes, it’s couched in terms of “this tornado is so severe, the usual advice doesn’t work” or “you can’t survive an EF5 above ground.” The message suggests that even in-residence shelters built to the design specifications of the Texas Tech wind engineering groups and the FEMA standards won’t survive.
This advice is wrong and providing it is irresponsible at best, and dangerous at worst. As a factual statement, claiming that EF5 tornadoes can’t be survived above ground is wrong. After the 3 May 1999 tornado that hit Moore, Oklahoma, survey work indicated that 1% of people who were in houses that were rated F4 or F5 were killed, as reported by Hammer and Schlimmin. They don’t differentiate between the F4 and F5 in the paper, but it is exceedingly unlikely that all of the people in F5 homes died. In the 20 May 2013 tornado, the Briarwood Elementary School was rated EF5 and there were no fatalities there. 1% may seem like a very small death rate, but it is orders of magnitude larger than the ordinary probability of dying in day to day activity. Violent tornadoes are very dangerous, but they do not bring certain death.
Of greater importance is the safety message and response it brings. Even if one believes that EF5 damage guarantees death, only a small part of the damage associated with tornadoes with peak damage of EF5 actually is EF5. As a result, even the pessimist would recognize that most people need to heed advice appropriate for their situations.
Consider the person who has no underground option readily at hand. What should they do? Flee the path? This potentially puts large numbers of people into vehicles ahead of the tornado. Past experience, such as the 1979 Wichita Falls tornado, teaches us that this is potentially catastrophic. Traffic jams occurred near the path on 20 May 2013 and it is exceptionally fortunate that deaths did not occur in vehicles in that tornado.
What if fleeing isn’t an option? There is a report of a young woman who had recently moved into a rent house and was unaware of whether any neighbors had a shelter. When she heard local television meteorologists say that she wouldn’t survive if she couldn’t get underground, she decided to run out of the path of the tornado. Fortunately, she called her mother who told her that this was a foolish thing to do and go back into the house and get into the closet where she rode out the tornado as it destroyed her house. She survived.
In the aftermath of the May 1999 tornado in Moore, we discovered that no school aged children had been killed in the tornado, and only one parent of a Moore Public School student was killed at home, out of the 36 fatalities. In an effort to understand why, I enlisted the help of an assistant principal and a teacher at two of the junior high schools in the Moore Public Schools that had had approximately half of their housing stock damaged or destroyed. We did some simple surveys of the 8th graders at their schools and talked to a large numbers of the students to find out what they knew about tornado safety and what they had done that evening. The overwhelming majority understood the basic rules as stated in the first sentence of this post and had taken appropriate action. They had taken the safety lessons they had learned at school and taken them home to protect their families.
Two stories stood out, however. There were two students who were in their homes, alone. The tornado came through the area in the early evening and their parents were not home at the time of the tornado. Both students were watching coverage of the tornado and heard the local television meteorologist say that if they didn’t get below ground, they would die. They had no underground shelter at the house and both had been told by their parents that they were not to leave the house until the parents got home. In both cases, the students faced a dilemma and both came to the same conclusion. They would obey their parents, stay in the house, and decided they would die in the tornado. They watched the coverage until the power went out. In one case, major damage occurred on the same block of houses.
Because of what they were told, they did absolutely nothing to protect themselves.
The message they were told that evening led to a potentially deadly lack of action.
We should be giving people the message that they should do what they can to protect themselves. Get as low as you can and put as many walls between you and the tornado as possible. In every violent tornado, stories come up along the lines of “how did anyone survive this?” The message from this is that it is possible to survive, but your chances are much better if you follow simple safety advice.
Some people have heard the message I am bringing and have misinterpreted it to mean that people shouldn’t get underground if that option is available to them. This is a grotesque reading of my words. Get low. If people don’t understand that “below ground” is lower than “above ground”, it’s not clear that there is a message we can provide them that they will understand.
We don’t know if the misguided advice that you won’t survive a tornado if you’re not underground has actually led to someone dying, but we do know that it has led to people making horribly bad decisions. Instead, we need to emphasize proper safety information to maximize the chances of survival.
Get as low as you can and put as many walls between you and the tornado as possible.
—Harold BrooksFollow @GFEmerMgmt