Another major, EF-5 tornado moved through the far western portion of the Oklahoma City area last Friday evening. With timely weather watches and warnings provided by the NWS in Norman, OK and Storm Prediction Center, and the devastation of the recent Moore tornado fresh on their minds, some people may have decided to get in their cars and drive out of the way of the approaching tornado. Such action may have led to traffic grid lock, leaving people in an unsafe condition trapped in traffic inside their cars as a strong tornado approached.
While very strong and violent tornadoes can destroy homes, you and your family are generally less at risk taking proper shelter in your home or other permanent building than you are in a car. Preliminary reports from Friday’s tornadoes in OK have the death toll at 9, most in vehicles. There were 9 additional fatalities in flash flooding, several of which occurred when victims took shelter from tornadoes in drainage ditches that ended up rapidly flooding. This serves as a reminder that tornadoes are not like hurricanes in terms of evacuation. Hurricane warnings are issued 24 to 36 hours in advance of the storm. Average lead time for tornado warnings is only about 13 minutes. If you are in an unsafe structure, the time to evacuate for stronger shelter is during the tornado watch or outlook phase, which is typically known hours to days before the storms hit. If you do evacuate for stronger shelter, make sure you let friends and family members know where you are going.
Our Norman NWS field office offers the following excellent tornado evacuation advice:
A car is an extremely dangerously place to be during a tornado. Tornadoes are capable of picking up even large cars and trucks and hurling them at high speeds hundreds of yards. Vehicles can also be impaled by flying debris. Violent tornados have been known to leave cars in mangled, almost unrecognizable, piles of steel. (http://www.spc.noaa.gov/faq/
Our Norman NWS field office offers the following excellent tornado safety advice:
Chicago is vulnerable to a major tornado strike during rush hour. The impact of an EF-3, EF-4 or EF-5 tornado on slowed or stopped rush hour traffic on area expressways and main arteries could be devastating. Attempting to drive out of the way of a tornado rather than shelter in place in a permanent building would worsen those consequences. Tens of thousands of people could be trapped in an unimaginable gridlock with little hope of getting in a substantial shelter to ride out the tornado. On a day when conditions are favorable for tornadoes, such as when a tornado watch is issued, you need to be able to get to a basement or interior room on the lowest floor of a home or business or other permanent structure within minutes or you are taking a risk. When a warning is issued for your location, or skies turn threatening when a watch is in effect, you should move to a storm shelter immediately.
The rash of tornadoes during May, including an EF-3 tornado that struck the St Louis metro area Friday evening, should serve as an important reminder of the power and fury of tornadoes and the vulnerability of even big cities like Chicago and Rockford. Everyone should make sure they have a plan of action in place at their home and their school or workplace of what to do when a tornado strikes. The time to make that plan is now, not when a tornado is approaching. The NWS Storm Prediction Center has a fantastic webpage detailing what to do to dramatically increase your chances of surviving a tornado, please consider incorporating the advice on this page (http://www.spc.noaa.gov/faq/