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HomeMy WebLinkAboutTornado Spotters Guide 1967 TABLE OF CONTENTS Page I. The W hy of Community Spotter Networks 1 II. Tornado Warning Information A. Tornado Watch 2 B. Tornado Warning 2 III. Tornado 2 Cha racteristics IV. Tornado 3 Development A. Parent Tor 5 nado Cloud B. Early Development 4 C. Formation of the Vortex 7 D. Lowering of Condensation Funnel 8 E. Mature Tornado 9 F. Development Summary 10 V. 11 Reporting Procedures VI. Public 13 Warning Signals 14 VII. Some Things to Look For 15 A. Funnel Behind Low Clouds B. Cummulus Mamma Formation 15 C. Twisted Horizontal Funnel 16 D. Secondary Funnels 17 lg VIII. References 19 IX. Photo Credits 20 ACKNOWLEDGMENTS The tornadoes at Dallas, Texas, April 2, 1957, were only two of the more than twenty tornadoes that occurred on this date over portions of Oklahoma, the Texas Panhandle, and north - central Texas. The Dallas tornadoes were unique in the hundreds of photographs taken by public spirited citizens which afforded researchers the first opportunity to study the complete life cycle of a tornado from photos of the funnel and related ground damage. Several of these photographs are shown in this guide to help civil defense weatherwatchers distinguish early vortex formation. Permission for use of these photos was obtained from private photographers (see page 20), all rights reserved. Dr. Vance Moyer, Professor of Meteorology and Acting Head of the Department of Meteorology, Texas A &M University, who has trained local spotter groups, helped prepare this material. Jake Canglose, Brazos County Civil Defense Director, also has contributed valuable assistance. Acknowledgment is given also to Bob Carpenter, Civil Defense Director, Comanche, Texas, and Joe Waring, Captain of Salvage and Rescue, Comanche Volunteer Fire Department, for permission to use their training material as a part of this guide. Mr. Waring, also an American Red Cross First Aid Instructor, has devoted considerable effort to safeguarding his community against the unannounced arrival of tornadoes. William A. McClung Rural Civil Defense Specialist Art Sketches by Bert Green lc THE WHY OF COMMUNITY SPOTTER NETWORKS Many communities have disaster relief and rehabilita- tion plans which describe actions to be taken following a disaster. However, even a few minutes advance warning of an approaching tornado can give people a chance to escape to comparative safety, thereby, perhaps preventing casualties and loss of life. For example, one school superintendent was quoted as saying that without the timely warning pro- vided by highway patrolmen and the local civil defense organization, 300 to 400 children would have been injured or killed.(1) Any town or city can be struck by tornadoes. Often warnings cannot be issued to a community in the path of a tornado, because of sudden storm development or because a tornado is not reported promptly. For this reason, each community should have its own reporting and warning system. Small communities should make provisions for receiving storm reports at a location where the town signaling device is located, such as the telephone exchange or fire depart - ment.(2) Lookouts should be posted during tornado fore- cast periods or when threatening storms are reported moving into the area. Training weatherwatch personnel is the responsibility of the local civil defense director. Residents in small communities or on ranches can provide valuable support and receive mutual cooperation by offering their services. This booklet was designed to help spotters recognize a tornado during its early development and make prompt, concise reports. Local officials may wish to supplement these instructions with a local directory and individual training. A set of tornado recognition slides is available for use in local training meetings. These slides may be scheduled through the Rural Civil Defense Office. The following Weather Bureau, E.S.S.A., publication is recommended as supplementary information:* "Tornado' (A brochure describing community and individual precautions against tornadoes.) *For sale by the Superintendent of Documents, U.S. Govern- ment Printing Office, Washington 25, D.C. 20402. Price- -$.20. -2- TORNADO WARNING INFORMATION FOR THE SPOTTER If you spot a tornado or funnel -cloud aloft from a safe distance, notify your local civil defense representa- tive immediately. In the event he or his deputy cannot be reached, contact the local law enforcement agency, county sheriff's office or Department of Public Safety headquarters.(3) Use the reporting format on page 13 to be sure your report is complete. TORNADO WATCH (ALSO TORNADO FORECAST) "60 MILES ON EITHER SIDE OF A LINE FROM COMANCHE TO WICHITA FALLS." THIS TYPE OF WARNING IS A FORECAST ONLY AND MEANS TO GO ON ABOUT YOUR NORMAL BUSINESS. KEEP TUNED TO A LOCAL RADIO OR TELEVISION STATION AND KEEP IN TOUCH WITH THE COMMUNITY WARNING CENTER. You may see nothing but sunshine. A tornado watch simply means storms are possible. TORNADO WARNING (ALSO TORNADO ALERT) This is given to all sources, including all police, civil defense, fire and school agencies. It sounds like this: "A SEVERE THUNDERSTORM IS MOVING FROM THE BANGS AREA IN A NORTHEASTERLY DIRECTION AT A FORWARD SPEED OF 15 MILES PER HOUR. RESIDENTS IN THE BROWN, COMANCHE AND ERATH COUNTY AREA SHOULD TAKE PRECAUTIONS FOR PERSONAL PROTECTION AND FOR PROTECTION OF PROPERTY. THIS STORM CONTAINS TORNADOES AND IMMEDIATE STEPS SHOULD BE TAKEN." Civil defense officials should be notified immediately. Weatherwatch units of civil defense should take station. Sheriff's units, highway patrol and schools should already have been alerted by law enforcement agencies, firemen or Weather Bureau personnel. -3- TORNADO CHARACTERISTICS Generally, a storm cell containing tornadoes moves from the southwest to the northeast. However, DON'T DEPEND ON IT; Tornadoes have been known to travel in every possible direction. They have been known to stand still, back up, go forward and then back up along the same track. They have been known to lash from side to side. For no apparent reason, they may go forward along a track, lift and appear on another track anywhere from 50 yards to 1/4 mile to one side, then move back. They are totally unpredictable in behavior. Tornadoes are most likely to occur in mid - afternoon, generally between 3 and 7 p.m. But, they have occurred at all times of day. Precipitation is often associated with a tornado. It generally occurs first as rain, frequently accompanied by hail just preceding the storm and as a heavy downpour immediately to the left of the tornado's path. Tornadoes have been known to cut a path of destruction anywhere from a few hundred feet to nearly 300 miles long.(:) The usual track is 10 to 20 miles. Therefore, watch any known funnel carefully until it dissipates, and then remain cautious until the storm has passed completely. If you have no chance to retreat from a tornado, the best protection is to take cover in an open ditch. You might attempt to drive away from one, but this is harzardous since a secondary funnel may form in front of you. Your best judgment must be used as to whether to take cover or try to escape. The noise of a tornado is loud and distinctive. When nearby, the roar is intense, often described as resembling the noise of several trains moving through a tunnel. When the funnel is well above the ground, a peculiar whine may be heard like the buzzing of many insects or airplane engines. These sounds may forewarn you of an approaching funnel. Don't turn in an alarm just because you hear them, but DO report suspicious noises. Funnel formation may start several thousand feet above the earth's surface, and some never reach the ground. Others touch the ground and rise again. Only the spinning funnel which reaches the ground is termed a tornado.