In meteorology, wind speed, or wind flow speed, is a fundamental atmospheric quantity caused by air moving from high to low pressure, usually due to changes in temperature. Wind speed is now commonly measured with an anemometer.
From May 2 to 8, 1999, a large tornado outbreak took place across much of the Central and parts of the Eastern United States, as well as southern Canada. During this week-long event, 152 tornadoes touched down in these areas. The most dramatic events unfolded during the afternoon of May 3 through the early morning hours of May 4 when more than half of these storms occurred. Oklahoma experienced its largest tornado outbreak on record, with 70 confirmed. The most notable of these was the F5 Bridge Creek–Moore tornado which devastated Oklahoma City and suburban communities. The tornado killed 36 people and injured 583 others; losses amounted to $1 billion, making it the first billion-dollar tornado in history. Overall, 50 people lost their lives during the outbreak and damage amounted to $1.4 billion. For these reasons, the outbreak is known in Oklahoma as the May 3rd outbreak or the Oklahoma tornado outbreak of 1999.
This article lists various tornado records. The most "extreme" tornado in recorded history was the Tri-State tornado, which spread through parts of Missouri, Illinois, and Indiana on March 18, 1925. It is considered an F5 on the Fujita Scale, holds records for longest path length at 219 miles (352 km) and longest duration at about 3+1⁄2 hours. The 1974 Guin tornado had the highest forward speed ever recorded in a violent tornado, at 75 mph (121 km/h). The deadliest tornado in world history was the Daulatpur–Saturia tornado in Bangladesh on April 26, 1989, which killed approximately 1,300 people. In the history of Bangladesh, at least 19 tornadoes killed more than 100 people each, almost half of the total for the world. The most extensive tornado outbreak on record was the 2011 Super Outbreak, which resulted in 367 tornadoes and 324 tornadic fatalities, whereas the 1974 Super Outbreak was the most intense tornado outbreak on tornado expert Thomas P. Grazulis's outbreak intensity score with 578, as opposed to the 2011 outbreak's 378.
The Late-May 1998 tornado outbreak and derecho was a historic tornado outbreak and derecho that began on the afternoon of May 30 and extended throughout May 31, 1998, across a large portion of the northern half of the United States and southern Ontario from southeastern Montana east and southeastward to the Atlantic Ocean. The initial tornado outbreak, including the devastating Spencer tornado, hit southeast South Dakota on the evening of May 30. The Spencer tornado was the most destructive and the second-deadliest tornado in South Dakota history. A total of 13 people were killed; 7 by tornadoes and 6 by the derecho. Over two million people lost electrical power, some for up to 10 days.
Timothy Patrick Marshall is an American structural and forensic engineer as well as meteorologist, concentrating on damage analysis, particularly that from wind, hail, and other weather phenomena. He is also a pioneering storm chaser and was editor of Storm Track magazine.
Doppler on Wheels is a fleet of X-band and C-band mobile and quickly-deployable truck-borne radars which are the core instrumentation of the Flexible Array of Radars and Mesonets affiliated with the University of Alabama Huntsville and led by Joshua Wurman, with the funding partially provided by the National Science Foundation (NSF), as part of the "Community Instruments and Facilities," (CIF) program. The DOW fleet and its associated Mobile Mesonets and deployable weather stations have been used throughout the United States since 1995, as well as occasionally in Europe and Southern America. The Doppler on Wheels network has deployed itself through hazardous and challenging weather to gather data and information that may be missed by conventional stationary radar systems.
Storm Chasers is an American documentary reality television series that premiered on October 17, 2007, on the Discovery Channel. Produced by Original Media, the program follows several teams of storm chasers as they attempt to intercept tornadoes in Tornado Alley in the United States. The show was canceled at the end of its 5th season by Discovery Communications on January 21, 2012.
The Verification of the Origins of Rotation in Tornadoes Experiment are field experiments that study tornadoes. VORTEX1 was the first time scientists completely researched the entire evolution of a tornado with an array of instrumentation, enabling a greater understanding of the processes involved with tornadogenesis. A violent tornado near Union City, Oklahoma was documented in its entirety by chasers of the Tornado Intercept Project (TIP) in 1973. Their visual observations led to advancement in understanding of tornado structure and life cycles.
Howard Bruce Bluestein is a research meteorologist known for his mesoscale meteorology, severe weather, and radar research. He is a major participant in the VORTEX projects. A native of the Boston area, Dr. Bluestein received his Ph.D. in 1976 from MIT. He has been a professor of meteorology at the University of Oklahoma (OU) since 1976.
Sean Cameron Casey is an American IMAX filmmaker and storm chaser who appeared in the Discovery Channel reality television series Storm Chasers. Casey created an IMAX film called Tornado Alley about chasing tornadoes and had to build the Tornado Intercept Vehicle (TIV) and the Tornado Intercept Vehicle 2 (TIV2) to film inside a tornado. Tornado Alley was released worldwide on March 18, 2011. Casey has been named one of the 50 best minds of 2008 by Discover Magazine.
The 2013 El Reno tornado was an extremely large, powerful, and erratic tornado that occurred over rural areas of Central Oklahoma during the early evening of Friday, May 31, 2013. This rain-wrapped, multiple-vortex tornado was the widest tornado ever recorded and was part of a larger weather system that produced dozens of tornadoes over the preceding days. The tornado initially touched down at 6:03 p.m. Central Daylight Time (2303 UTC) about 8.3 miles (13.4 km) west-southwest of El Reno, rapidly growing in size and becoming more violent as it tracked through central portions of Canadian County. Remaining over mostly open terrain, the tornado did not impact many structures; however, measurements from mobile weather radars revealed extreme winds in excess of 313 mph (504 km/h) within the vortex. These are among the highest observed wind speeds on Earth, just slightly lower than the wind speeds of the 1999 Bridge Creek–Moore tornado. As it crossed U.S. 81, it had grown to a record-breaking width of 2.6 miles (4.2 km), beating the previous width record set in 2004. Turning northeastward, the tornado soon weakened. Upon crossing Interstate 40, the tornado dissipated around 6:43 p.m. CDT (2343 UTC), after tracking for 16.2 miles (26.1 km), it avoided affecting the more densely populated areas near and within the Oklahoma City metropolitan area.
The following is a glossary of tornado terms. It includes scientific as well as selected informal terminology.
Jeffrey W. Frame is an American atmospheric scientist and professor at the University of Illinois at Urbana-Champaign. He is known for observational and modeling studies of severe convective storms and for teaching meteorology. He was a scientist for VORTEX2 and other field research programs.
Donald W. Burgess is an American meteorologist who has made important contributions to understanding of severe convective storms, particularly tornadoes, radar observations and techniques, as well as to training other meteorologists. He was a radar operator during the first organized storm chasing expeditions by the University of Oklahoma (OU) in the early 1970s and participated in both the VORTEX projects.
Edwin Kessler III was an American atmospheric scientist who oversaw the development of Doppler weather radar and was the first director of the National Severe Storms Laboratory (NSSL).
The Shared Mobile Atmospheric Research and Teaching Radar, colloquially known as SMART-R or SR, is a mobile Doppler weather radar platform operated and created by University of Oklahoma (OU) with aide from Texas A&M and Texas Tech University in 2001.
On the afternoon of May 21, 2024, a violent, destructive and powerful multi-vortex tornado struck the communities of Villisca, Nodaway, Brooks, Corning, and Greenfield in southwestern Iowa, killing five people and injuring 35 others. The tornado was the strongest of a large widespread tornado outbreak that occurred from May 19–27, 2024 in the central United States. The tornado reached peak intensity in the city of Greenfield, leading the National Weather Service in Des Moines, Iowa to assign a rating of mid-range EF4 on the Enhanced Fujita scale, with maximum wind speeds estimated at 185 mph (298 km/h). However, winds of 309–318 mph (497–512 km/h) were measured in a sub-vortex of the tornado by a DOW, placing it among the strongest tornadoes ever measured.
A descending reflectivity core (DRC), sometimes referred to as a blob, is a meteorological phenomenon observed in supercell thunderstorms, characterized by a localized, small-scale area of enhanced radar reflectivity that descends from the echo overhang into the lower levels of the storm. Typically found on the right rear flank of supercells, DRCs are significant for their potential role in the development or intensification of low-level rotation within these storms. The descent of DRCs has been associated with the formation and evolution of hook echoes, a key radar signature of supercells, suggesting a complex interplay between these cores and storm dynamics.
Starting in the mid-1900s, mobile radar vehicles were being used for academic and military research. In the late 1900s, mobile doppler weather radars were designed and created with the goal to study atmospheric phenomena.
In the afternoon hours of June 5, 2009, a well-documented tornado moved across Goshen County, located in the state of Wyoming. The tornado was observed by hundreds of experimental radar instruments, and the event formed the pinnacle of the VORTEX projects, which aimed to document the formation and lifecycle of a tornado. The tornado and the observations of it were heavily studied by meteorologists in the following years, and footage of the tornado has been featured on several national television networks, including The Weather Channel.
