http://scitech.quickfound.net/weather_news_and_links.html Twister - Federal Emergency Management Agency - Depicts the response to and aftermath of a tornado disaster on May 11, 1970 at Lubbock, Texas. Public domain film from the US National Archives, slightly cropped to remove uneven edges, with the aspect ratio corrected, and mild video noise reduction applied. The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and/or equalization (the resulting sound, though not perfect, is far less noisy than the original). http://creativecommons.org/licenses/by-sa/3.0/ https://en.wikipedia.org/wiki/1970_Lubbock_tornado The 1970 Lubbock tornado was a tornado event that occurred in Lubbock, Texas, on May 11, 1970. It was one of the worst tornadoes in Texas history, and occurred exactly 17 years to the day after the deadly Waco Tornado. It is also the most recent F5 tornado to have struck a central business district of a large city... At 8:10PM, an off-duty Lubbock police officer spotted a funnel cloud on the east side of the city, and grapefruit-size hail was reported. At 8:15, local radar indicated a hook echo and a tornado warning was issued for Lubbock and Crosby counties, and the first tornado to strike the city touched down seven miles south of Lubbock Municipal Airport... The second tornado was devastating, affecting a 25-square-mile (65 km2) area or roughly a quarter of Lubbock. Hardest hit were the inner city commercial and residential areas, the light industrial area south of Loop 289, and the residential area north of Loop 289 and the Lubbock Municipal Airport. A total of 430 homes were destroyed, 519 sustained major damage, and 7,851 more sustained minor damage... Damage totaled $250 million, ($1,411,900,000 in 2008 dollars), making it the costliest U.S. tornado until it was surpassed by the Omaha Tornado of 1975. The storm's final death toll was 26... https://en.wikipedia.org/wiki/Tornado A tornado is a violently rotating column of air that is in contact with both the surface of the earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. They are often referred to as twisters or cyclones, although the word cyclone is used in meteorology, in a wider sense, to name any closed low pressure circulation. Tornadoes come in many shapes and sizes, but they are typically in the form of a visible condensation funnel, whose narrow end touches the earth and is often encircled by a cloud of debris and dust. Most tornadoes have wind speeds less than 110 miles per hour (180 km/h), are about 250 feet (80 m) across, and travel a few miles (several kilometers) before dissipating. The most extreme tornadoes can attain wind speeds of more than 300 miles per hour (480 km/h), stretch more than two miles (3 km) across, and stay on the ground for dozens of miles (more than 100 km). Various types of tornadoes include the landspout, multiple vortex tornado, and waterspout. Waterspouts are characterized by a spiraling funnel-shaped wind current, connecting to a large cumulus or cumulonimbus cloud. They are generally classified as non-supercellular tornadoes that develop over bodies of water, but there is disagreement over whether to classify them as true tornadoes. These spiraling columns of air frequently develop in tropical areas close to the equator, and are less common at high latitudes. Other tornado-like phenomena that exist in nature include the gustnado, dust devil, fire whirls, and steam devil; downbursts are frequently confused with tornadoes, though their action is dissimilar. Tornadoes have been observed on every continent except Antarctica. However, the vast majority of tornadoes occur in the Tornado Alley region of the United States, although they can occur nearly anywhere in North America. They also occasionally occur in south-central and eastern Asia, northern and east-central South America, Southern Africa, northwestern and southeast Europe, western and southeastern Australia, and New Zealand. Tornadoes can be detected before or as they occur through the use of Pulse-Doppler radar by recognizing patterns in velocity and reflectivity data, such as hook echoes or debris balls, as well as through the efforts of storm spotters. There are several scales for rating the strength of tornadoes. The Fujita scale rates tornadoes by damage caused and has been replaced in some countries by the updated Enhanced Fujita Scale. An F0 or EF0 tornado, the weakest category, damages trees, but not substantial structures. An F5 or EF5 tornado, the strongest category, rips buildings off their foundations and can deform large skyscrapers. The similar TORRO scale ranges from a T0 for extremely weak tornadoes to T11 for the most powerful known tornadoes. Doppler radar data, photogrammetry, and ground swirl patterns (cycloidal marks) may also be analyzed to determine intensity and assign a rating...

• published: 01 Jul 2015
• views: 17