Helpful tips for July 2014

| Overview | Myths and Facts | Safety: [ Preparation | Watches | Warnings | Outdoors | Afterwards ] Tornado Myths and Facts “When confronted by a tornado warning, you should open all the windows in your house to equalize the pressure.” MYTH: This just wastes valuable time. Don’t worry about equalizing the pressure, the roof ripping off and the pickup truck smashing through the front wall will equalize the pressure for you. “I live in a big city, a tornado wouldn’t hit a big city.” MYTH: Tornadoes have hit several large cities, including Dallas, Oklahoma City, Wichita Falls, St. Louis, Miami, and Salt Lake City. In fact, an urban tornado will have a lot more debris to toss around than a rural twister. A tornado approaches downtown Dallas, TX on 02 April, 1957 NOAA library page The path of the May 3, 1999 F5 tornado that tore through downtown Oklahoma City From KFOR-TV, Oklahoma “Tornadoes don’t happen in the mountains.” MYTH: Tornadoes do occur in the mountains. Damage from an F3 tornado was documented above 10,000 feet, and a hiker in the mountains of Utah photographed a weak tornado in the mountains. “Tornadoes may occur in the middle of the night and even during the winter.” FACT: Although the likelihood is lower at night and during colder months, tornadoes have caused death and destruction during these times of day and year. Violent tornadoes, while very unlikely during the winter months, do occasionally occur at night. When severe weather is forecast, ensure your NOAA weather radio is on and working properly before you go to bed. “My city doesn’t get tornadoes because it is protected by a river.” MYTH: Many tornadoes have crossed rivers and even gone on to cause widespread damage to riverside cities. For example, the Nachez, Mississippi tornado of 1840 tracked directly down the Mississippi River, killing hundreds, mostly on the water. view the photo here: tology Others have crossed large rivers without losing speed (they momentarily became water spouts) and devastated cities that folklore had thought immune to tornadoes. An example was the Waco, TX tornado of 1953 that crossed the Brazos River, seen at this link. tology or the Great St. Louis Cyclone of 1896 that jumped the Mississippi River. Seen at this link. tology “Tornadoes have picked people and items up, carried them some distance and then set them down without injury or damage.” FACT: People and animals have been transported up to a quarter mile or more without serious injury. Fragile items, such as sets of fine china, or glass-ware have been blown from houses and recovered, miles away, without any damage. However, given the quantity of airborne debris, these occurrences are the exception, rather than the norm. “Hiding under a freeway overpass will protect me from a tornado.” MYTH: While the concrete and re-bar in the bridge may offer some protection against flying debris, the overpass also acts as a wind tunnel and may actually serve to collect debris. When you abandon your vehicle at the overpass and climb up the sides, you are doing two things that are hazardous. First, you are blocking the roadway with your vehicle. When the tornado turns all the parked vehicles into a mangled, twisted ball and wedges them under the overpass, how will emergency vehicles get through? Second, the winds in a tornado tend to be faster with height. By climbing up off the ground, you place yourself in even greater danger from the tornado and flying debris. When coupled with the accelerated winds due to the wind tunnel (Venturi Effect), these winds can easily exceed 300 mph. Unfortunately, at least three people hiding under underpasses during tornadoes have already been killed, and dozens have been injured by flying debris. If you realize you won’t be able to outrun an approaching tornado, you are much safer to abandon your vehicle, and take shelter in a road-side ditch or other low spot (see Tornado Safety ). For more information on the use of highway overpasses for shelter, please see this NWS discussion on highway overpasses . Note: If a highway overpass is your only shelter option, only consider it if the overpass has sturdy roadway supports, next to which (at ground level) you can take shelter. Avoid the smooth concrete, support-less spans at all costs. “I can outrun a tornado, especially in a vehicle.” MYTH: Tornadoes can move at up to 70 mph or more and shift directions erratically and without warning. It is unwise to try to outrace a tornado. It is better to abandon your vehicle and seek shelter immediately. “While there is no such thing as a category 6 hurricane (the Saffir-Simpson Hurricane Scale only goes to category 5), there can be an F6 tornado.” This tornado scale can be seen here: FACT: The Fujita Tornado Damage Intensity Scale actually goes up to F12! Check out the photo here: The F12 level only begins at wind speeds exceeding Mach 1.0 (or around 738 mph at -3]]>

This entry was posted in Uncategorized. Bookmark the permalink.