When hearing the word “twister,” one may conjure up images of a game involving a spinner and a vinyl sheet adorned with colored circles that became popular after Johnny Carson and Eva Gabor played it on the Tonight Show in May 1966. Perhaps one sees actor Bill Paxton chasing his “movie wife” Helen Hunt in order to deliver divorce papers before getting caught in a series of intense storms in Oklahoma in the 1996 movie Twister. However, those individuals who have survived the wrath of one of Mother Nature’s most devastating weather phenomena may recall a much more terrifying image.
A twister, another name for a tornado, is a violently rotating column of air extending between and remaining in contact with a cloud and the surface of the earth. It may appear with an accompanying funnel cloud, and there are no predictable patterns of rain, hail, lightening, or wind. (When these climatic occurrences form over water they are know as water spouts.) Tornadoes may achieve wind speeds in excess of 200 miles per hour.
Tornadoes originally were measured according to the Fujita Scale, or F-scale, named after T. Theodore Fujita, MD, who introduced the measurement system in 1971 to relate the degree of damage to the intensity of the wind. A much more precise Enhanced Fujita (EF) Scale has replaced the original scale and goes from EF 0 (65–85 mile per hour winds) all the way up to EF 5 (more than 200 miles per hour).*
Tornadoes can occur anywhere in the world but most frequently happen in the U.S., especially east of the Rocky Mountains. Oklahoma City has the distinction of being the city that has experienced the most tornadoes (more than 100). On average, roughly 1,300 tornadoes occur yearly, accounting for approximately 60 deaths. However, in 2011, the deadliest year on record, a total of 1,691 tornadoes resulted in 550 deaths in 15 states. Several of these tornadoes reached EF 5 level winds.*
To examine the occurrence of tornado-related injuries in the National Trauma Data Bank® research dataset for 2010, admissions records were searched using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM). Specifically searched was external cause of injury E code 908.1 (injuries due to natural and environmental factors: tornado, cyclone, twister). A total of 101 records were found. In all, 72 records contained a hospital discharge status, including 48 discharged to home, 12 to acute care/rehab, and nine sent to skilled nursing facilities; there were three fatalities. Of these patients, 53.5 percent were male, on average 44.1 years of age, had an average hospital length of stay of 5.2 days, an intensive care unit length of stay of 5.9 days, were on the ventilator for an average of 7.4 days, and had an average injury severity score of 12.3 (see figure).
The Storm Prediction Center of the National Oceanic and Atmospheric Administration may issue a tornado watch for areas expecting hail measuring one inch in diameter or greater along with damaging winds and the possibility of tornadoes. These watch areas typically cover 25,000 square miles, about half the size of Iowa. If you find yourself in one of these watch areas and are inside, it is recommended that you follow these steps: go to the lowest floor, preferably a basement; position yourself in a centrally located area of the room; avoid windows; seek protection from possible falling items; cover yourself with thick padding, such as a blanket or mattress, or put on a helmet; crouch down; and cover your head. If you find yourself outside, seek shelter in a sturdy building, if possible; otherwise, lie face down, flat, on low ground as far away as possible from trees and cars, and protect the back of your head with your arms. Remember, Twister may be a fun-filled game, but a tornado is a life-threatening climatic occurrence.
Throughout the year, we will be highlighting data through brief reports in the Bulletin. The National Trauma Data Bank Annual Report 2011 is available on the ACS website as a PDF file and as a PowerPoint presentation at www.ntdb.org. In addition, information is available on our website about how to obtain NTDB data for more detailed study. If you are interested in submitting your trauma center’s data, contact Melanie L. Neal, Manager, NTDB, at email@example.com.
Statistical support for this article has been provided by Chrystal Price, data analyst, NTDB.
* National Oceanic and Atmospheric Administration. The Storm Prediction Center. Available at: http://www.spc.noaa.gov/faq/tornado/. Accessed April 12, 2012.