Friday, May 23, 2014

Cars and Tornado Safety: Rethinking Conventional Wisdom

Tim Samaras car

For decades, conventional wisdom has said that a car is the worst place to be caught during a tornado, besides maybe a mobile home. Hundreds of photos of demolished vehicles thrown about by violent twisters seem to provide ample support for that conclusion. Driving instructors, safety advocates, and meteorologists have all argued that a ditch or culvert provides better protection than an easily-overturned car. Over the last decade or so, however, a debate has been brewing between weather and safety experts about the soundness of this advice.

About five years ago, the American Red Cross revised its guidelines for motorists caught in the path of a tornado. Instead of encouraging drivers to abandon their vehicles and seek shelter in a ditch or culvert, the group advises that "your choice should be driven by your specific circumstances." You should only ditch your car "if you can safely get noticeably lower than the level of the roadway." Otherwise, the group claims, you're better off staying in your car with your seatbelt buckled and your head tucked below the level of the glass. The group further advises that you're better off "abandon[ing] your mobile home immediately" and seeking shelter in a vehicle than trying to ride out a tornado in a house trailer.  Of course, a basement or "sturdy shelter" of any type is preferable to these options.

As Dr. Greg Forbes of the Weather Channel explained in this article from 2009, these new guidelines provoked controversy. They contradicted many years of advice and advocacy from various safety groups, including the National Weather Service (NWS). The Red Cross justified its new stance in part by referencing the work of weather researcher Thomas Schmidlin and his partners, including this paper. In that article, the researchers found that stationary vehicles were rarely overturned by low-to-medium strength tornadoes; they based their conclusions on damage surveys as well as wind-tunnel tests. It seemed reasonable to conclude that stationary vehicles offered better protection from tornado-force winds than easily destroyed mobile homes or foregoing protection entirely. However, the group's report avoided drawing conclusions about the effect of tornado-force winds on moving vehicles, citing insufficient data.

Another hot-button issue is the ability of cars to evade tornadoes in the first place. Several groups now argue that this is possible and can be attempted, but only in limited circumstances. Dr. Forbes recommends driving at a right angle away from the tornado in his article, if you can determine the direction of its path and if the way ahead is clear. The Weather Channel's official guidelines advise that "if you can safely drive away from the tornado, do so." Ready.gov, the Federal Emergency Management Agency's public outreach site, says that you should never attempt to outrun a tornado in "urban or congested areas." Highways and rural areas are unmentioned, leaving the door open for escape attempts when the road is clear. However, the Centers for Disease Control disagrees sharply with that recommendation. So does weather-forecasting site AccuWeather, which advises against both outrunning a tornado in your car and staying inside a vehicle once a tornado is spotted.

Despite this controversy, many groups and agencies have issued updated guidelines in the last several years. The NWS now echoes the Red Cross in its recommendations; so does FEMA. The CDC seems to be alone amongst federal agencies in continuing to advocate the older approach. All the agencies and groups surveyed agree on one point, though: overpasses and bridges will NOT protect you from a tornado. These exposed structures actually increase your chance of being injured. Even lying in a field is less risky than hunkering under an overpass or a bridge abutment.

Although it's not hinted at in any of these safety guidelines, another reason the conventional wisdom is changing may be advances in vehicle technology. The average car or truck of today is far more crush-resistant than the vehicles of twenty or more years ago. That, coupled with the fact that even inexpensive cars now have a plethora of airbags and crumple zones, makes impacts much more survivable. Weather Channel meteorologist Mike Bettes and his support crew survived this crash last year while filming the El Reno tornado, the widest twister in recorded history. Their GMT900 Suburban showed the dividends of a highly reinforced body shell coupled with an extensive airbag and restraint system. Although the roof partly caved in, it was a far cry from the early days of tin-can SUVs with weak structures like the first-generation Explorer, 4Runner, and Samurai.

Not everyone caught out by the El Reno twister was so lucky. Veteran storm chaser Tim Samaras, his son Paul, and research partner Carl Young all died when their Cobalt, pictured above, was lifted from the road and virtually obliterated by the tornado. Their deaths, as well as Bettes' accident, led to a reevaluation of TWC's protocol for covering tornadoes; camera crews and chasers now hang farther back from the path of the storm.  What can we learn from this debate? Mostly, that riding out a tornado in your car is still a risky proposition. A secure shelter like a basement or a bathroom is always a better alternative, if it can be found in time. Improved vehicle technology has increased the likelihood of your survival if you are caught out by a twister, at least in relatively weak storms. However, powerful tornadoes with 300 mph winds like the El Reno monster are more than enough to destroy most road-going vehicles. The best protection is still prevention: stay off the road when you know a tornado might be in your path.



from The Truth About Cars http://ift.tt/Jh8LjA

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