The 1948 Tinker Air Force Base tornadoes were two

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. It is often referred to as a twister, whirlwind or cyclone, altho ...

es which struck

Tinker Air Force Base Tinker Air Force Base is a major United States Air Force base, with tenant U.S. Navy and other Department of Defense missions, located in Oklahoma County, Oklahoma, surrounded by Del City, Oklahoma City, and Midwest City. The base, origina ...

Oklahoma City Oklahoma City (), officially the City of Oklahoma City, and often shortened to OKC, is the capital and largest city of the U.S. state of Oklahoma. The county seat of Oklahoma County, it ranks 20th among United States cities in population, a ...

, Oklahoma, on March 20 and 25, 1948. Both are estimated to have been equivalent to F3 in intensity on the modern

Fujita scale The Fujita scale (F-Scale; ), or Fujita–Pearson scale (FPP scale), is a scale for rating tornado intensity, based primarily on the damage tornadoes inflict on human-built structures and vegetation. The official Fujita scale category is determ ...

of tornado intensity, which was not devised until 1971. The March 20 tornado was the costliest tornado in Oklahoma history at the time. On March 25,

meteorologist A meteorologist is a scientist who studies and works in the field of meteorology aiming to understand or predict Earth's atmospheric phenomena including the weather. Those who study meteorological phenomena are meteorologists in research, while t ...

s at the base noticed the extreme similarity between the weather conditions of that day and March 20, and later in the day issued a "tornado forecast", which was verified when a tornado struck the base that evening. This was the first official tornado forecast, as well as the first successful tornado forecast, in recorded history.

March 20 tornado

Weather forecasting was still crude and prone to large errors in the era before

weather satellite A weather satellite or meteorological satellite is a type of Earth observation satellite that is primarily used to monitor the weather and climate of the Earth. Satellites can be polar orbiting (covering the entire Earth asynchronously), or ge ...

s and computer modeling. Thunderstorms were not even in the forecast for the evening of March 20. However, around 9:30 pm storms were reported about to the southwest, and at 9:52 a tornado was sighted near

Will Rogers Airport Will Rogers World Airport , Will Rogers Airport or simply Will Rogers, is a passenger airport located in Oklahoma City, Oklahoma, United States, about 6 miles (10 km) southwest of the city's downtown area. It is a civil-military airport ...

away, along with a wind gust, moving northeast towards the base. At 10:00, the tornado reached the southwest corner of the base. Illuminated by nearly constant lightning, the tornado was highly visible as it bisected the base, tossing around planes which were parked in the open. The

control tower Air traffic control (ATC) is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through a given section of controlled airspace, and can provide advisory services to aircraft in non-controlled airsp ...

reported a wind gust before the windows shattered, injuring several personnel with flying glass. The tornado dissipated at the northeast corner of the base. The tornado missed most structures on the base, but the damage to expensive military aircraft was substantial. The total damage cost came to around $10 million, or $ million in United States dollars. This was the most damaging tornado in

Oklahoma Oklahoma (; Choctaw language, Choctaw: ; chr, ᎣᎧᎳᎰᎹ, ''Okalahoma'' ) is a U.S. state, state in the South Central United States, South Central region of the United States, bordered by Texas on the south and west, Kansas on the nor ...

up to that date.

Investigation and tornado forecast

In the aftermath of the first tornado, an official inquiry was conducted into the failure to predict the destructive tornado. Air Force investigators came to the conclusion that "due to the nature of the storm it was not forecastable given the present state of the art." They also made recommendations that the meteorological community determine a tornado warning system for the public, as well as a protocol for protecting life and property at military bases. Both of these investigations began almost immediately. In the days following the tornado, Tinker's meteorologists Major Ernest J. Fawbush and Captain

Robert C. Miller Col. Robert C. Miller, USAF (1920–1998), was an American meteorologist, who pioneered severe convective storms forecasting and applied research, developing an empirical forecasting method, identifying many features associated with severe thunder ...

investigated

surface A surface, as the term is most generally used, is the outermost or uppermost layer of a physical object or space. It is the portion or region of the object that can first be perceived by an observer using the senses of sight and touch, and is ...

and upper-air weather data from this and past tornado outbreaks, hoping to be able to identify conditions which were favorable for tornadoes. By March 24, they had compiled several possible tornado indicators, and decided it would be difficult, but possible, to identify large tornado threat areas in the future. On the morning of March 25, base meteorologists noticed that weather charts for the day were strikingly similar to those before the March 20 tornado. Forecasts issued by the

Weather Bureau The National Weather Service (NWS) is an agency of the United States federal government that is tasked with providing weather forecasts, warnings of hazardous weather, and other weather-related products to organizations and the public for the ...

indicated that almost the same conditions would be present in the evening of March 25 as were present on March 20. In the morning, they issued a forecast for "heavy thunderstorms" effective for 5–6 pm that evening. This would allow the base's commander to alert base personnel that they may institute their brand-new tornado precautions. As the day wore on, conditions appeared more and more favorable for thunderstorms, and more and more similar to the events of March 20.

Weather radar Weather radar, also called weather surveillance radar (WSR) and Doppler weather radar, is a type of radar used to locate precipitation, calculate its motion, and estimate its type (rain, snow, hail etc.). Modern weather radars are mostly puls ...

images showed a severe

squall line A squall line, or more accurately a quasi-linear convective system (QLCS), is a line of thunderstorms, often forming along or ahead of a cold front. In the early 20th century, the term was used as a synonym for cold front (which often are accompa ...

had formed to the west, and

weather station A weather station is a facility, either on land or sea, with instruments and equipment for measuring atmospheric conditions to provide information for weather forecasts and to study the weather and climate. The measurements taken include tempera ...

s to the west reported

cumulonimbus cloud Cumulonimbus (from Latin ''cumulus'', "heaped" and ''nimbus'', "rainstorm") is a dense, towering vertical cloud, typically forming from water vapor condensing in the lower troposphere that builds upward carried by powerful buoyant air currents. ...

s and thunderstorms. In an afternoon meeting, under some pressure from their commanding officer, base meteorologists composed and issued the first official tornado forecast. Although they were aware of the small chance of success, they felt they had no choice, since the conditions were so similar to March 20. Equipment, which could be, was moved to bomb-proof shelters, and base personnel were moved to safer areas.

March 25 tornado

Although storms were relatively benign up to the point where they reached Tinker, a

supercell A supercell is a thunderstorm characterized by the presence of a mesocyclone: a deep, persistently rotating updraft. Due to this, these storms are sometimes referred to as rotating thunderstorms. Of the four classifications of thunderstorms (s ...

formed just west of the base, and at around 6 pm a tornado touched down on the base for the second time in six days. This second tornado caused $6 million in damage, or $ million in dollars. However, due to precautions enacted because of the tornado forecast, no injuries were reported, and damage totals could have been much higher.

Legacy

The tornado prediction proved to be successful, even if its precision was mostly due to chance. Before this point, the

had a policy against issuing tornado warnings, mainly due to fear of panic by the public, and subsequent complacency if forecasts turned out to be false alarms. Due to lives and costs saved, Fawbush and Miller continued their tornado forecasts, which verified at quite a high rate over the next three years. At first, they kept their forecasts secret. In the spring and summer of 1949, they issued eighteen forecasts for tornadoes within a area, and all eighteen proved successful. In the subsequent years, while not explicitly using the word "tornado", the Weather Bureau used the pair's forecasts to predict "severe local storms". The synoptic pattern which occurred on March 25 later became known as the " Miller type-B" pattern and is recognized as one of the most potent severe weather setups.

References

Bibliography