A UNITED STATES DEPARTMENT OF COMMERCE PUBLICATION NO A A Photoessay No. 2: V SKYWARN The tornado — SKYWARN's reason for being. Most violent wind on earth, torna- does leave trails of virtually complete de- struction. SKYWARN volunteers, communi- ty and individual tornado preparedness, and the storm warnings of the National Weather Service combine to reduce the number of human casualties when such de- struction comes. Photoessay No. 2: SKYWARN The approach of spring brings an unsettled period of American weather. The advance of warm weather means that warm, wet air off the tropical oceans and dry tongues of desert air from the southwest will open their annual springtime offensive against the cold, re- treating flanks of continental winter. The battle begins over the central Gulf states, then, in March and April, shifts eastward through Georgia to the sea. It touches the southern plains in May, the northern plains and Great Lakes states in June. And, through the year, there are the isolated, random skirmishes of any large campaign. This competition between warm and cold, moist and dry, liberates massive amounts of energy into the atmos- phere, and breeds nature's most familiar form of vio- lence — thunderstorms, and their dangerous attendants: lightning, hail, high winds, heavy rains, and the violent whirlwinds called tornadoes. The National Weather Service of NOAA, the U.S. Com- merce Department's National Oceanic and Atmospheric Administration, warns Americans that such violence is on the way. From the National Severe Storms Forecast Center in Kansas City, Mo., severe weather watches are issued describing areas of possible thunderstorm and tornado activity. Then, as the emergency matures, warn- ing operations shift to the locally affected offices of the National Weather Service, and to their networks of SKY- WARN volunteers, whose eyes are still the best tornado- detectors around. SKYWARN is NOAA's word for what the volunteer storm spotters do. It also describes the annual effort to make Americans tornado-conscious and tornado-ready. These deadly storms strike swiftly, and may occur any- where, at any time. Tornado preparedness is the only way to keep tornado casualties low. This publication tells some of the SKYWARN story in photographs, reproduced here in screened form for line reproduction. They are also available as 8 x 10 inch, black and white glossy prints, from: Photo Editor Office of Public Information National Oceanic and Atmospheric Administration Rockville, Maryland 20852 Please credit: "NOAA Photo". SKYWARN preparedness begins while the sky is blue, and while it darkens with thunderclouds. A mature thunderstorm system may be several miles across its base and tower to altitudes of 60,000 feet or more — the higher the cloud top, the more intense the storm. Some form as lonely giants, some as a line of raging storms along a front. With or without tornadoes, a mature thunderstorm can cause death and damage with its high winds, heavy rains, hail, and lightning. Lightning, the thunderbolt of mythology, kills more Ameri- cans most years than hurri- canes or tornadoes. To SKY- WARN observers, lightning is an indication of thunderstorm intensity: usually, the more lightning observed, the more violent the storm system. Al- though specific warnings against lightning are not given, SKYWARN preparedness sees the implicit warning of light- ning in any forecast of thun- derstorms. Hail is a key event for SKYWARN observers, for its appearance in- dicates that the thunderstorm system has entered a very intense phase. The larger the hail, generally speaking, the more intense the storm. When hail begins, watch out for tornadoes. The adolescence and maturity of a tornado was photographed near En,d Oklahoma ^^^"^. ^^ 966 _Th.n, light-colored funnel cloud touches down (1), darkens as dirt and debris f low up mto the violent wmds (2), thickens and grows coarser (3) as it reaches a ropeshaped, frightenmg maturity (4). '^^ Meteorologists at the National Severe Storms Forecast Center in Kansas City, Mo., monitor conditions in the North American atmosphere using surface data from hundreds of points, radar summaries, satellite photo- graphs, meteorological upper-air profiles (obtained by sounding balloons), and reports from pilots. From these thousands of pieces of information, weathermen determine the area that is most likely to experience severe weather. Information on this area is then issued to National Weather Service Offices and the public in the form of a watch bulletin. The near-continuous view provided by geostationary Applications Technology Satellite (ATS) 3 permits Na- tional Severe Storm Forecast Center meteorologists to watch dangerous thunderstorm activity as it actually happens. This new storm-watching capability may contribute to more effective forecasts of hazardous weather. Shown here, the thundercloud system which spawned tornadoes near Lubbock, Texas, in May 1970 as seen from the ATS 3 satellite. Commerce Department scientists at the National Severe Storms Forecast Center determine the area covered by a tornado watch. Watch areas are usually about 140 miles wide by 240 miles long. The message describes what is expected, where, and for how long. A watch is not a warning, but only indicates the possibility of hazardous weather in the area and time period specified. Local offices of the National Weather Service, once alerted by a tornado or severe thunderstorm watch bulle- tin monitor the atmosphere over their area for signs of dangerous activity— high wmds, heavy ram, hail, in- tense lightning rotary cloud motion. Here, while one meteorologist watches the radarscope, another stays on the telephone to the SKYWARN net. Between them, they can blunt the edge of a tornado disaster in their community. Radar is one of the meteorologist's most useful torna- do-detecting devices. Here, tell-tale echoes picked up by the Amarillo, Texas, radar indicates a tornado (arrow) forming near Lubbock. Timely warning and the tornado-consciousness of its citizens kept Lub- bock's casualties down when the twister roared through an hour later. The human eye is still the only positive detector of tornadoes, and the eyes of SKYWARN volunteers across the Nation provide the first line of defense against these destructive storms. SKYWARN volun- teers may be law enforcement personnel, farmers, factory workers, housewives — public-spirited citizens who help the National Weather Service watch our dangerous skies. ''^TifJi'^,!!,"'^'^^"^'"^ LIBRARIES ADDDD7EDm7Sfl Remember Main Street? It was here, a minute ago. Before the tornado. When you hear a National Weather Service warning it means a tornado has been detected nearby. Watch for the funnel cloud. Listen for the roar. Take cover below ground level or in a solid shelter. Curl up and shield your head and eyes. If you live in a mobile home, leave it for solid shelter or low ground. The warning means you are out of time. Save your life. Save the lives of those who cannot save themselves. Forget Main Street. You can start rebuilding it, a minute later. This message from the National Oteanic and Almospherit- \