TWISTEX (a backronym for Tactical Weather-Instrumented Sampling in/near Tornadoes Experiment) was a tornado research experiment that was founded and led by Tim Samaras of Bennett, Colorado, US, that ended in the deaths of three researchers in the 2013 El Reno tornado. The experiment announced in 2015 that there were some plans for future operations, but no additional information has been announced since.
Background
The project normally ran from mid-April through the end of June with a domain that covers the Great Plains and portions of the Midwestern United States. The project was normally at full strength for most of May and June with four vehicles, all equipped with roof-mounted mobile mesonet weather stations. One of the vehicles transported an array of in situ thermodynamic and video probes. Due to graduate and upper-division undergraduate student participant availability, a reduced vehicle compliment consisting of the in situ probe deployment truck and one support mesonet station vehicle was used in the first few weeks of the project.
The research objectives were to better understand tornado generation, maintenance and decay processes and to gain insight and knowledge of the seldom sampled near-surface internal tornado environment. Progress on these research fronts was aimed toward increasing tornado warning lead time, while the internal tornado near-surface sampling provided essential ground truth data for structural engineering analysis of the interaction of tornadic winds with homes and buildings.
TWISTEX was one of the featured teams in seasons 3, 4 and 5 of Storm Chasers on the Discovery Channel. The group was also featured on National Geographic Channel's "Disaster Labs".
May 31, 2013 deaths
On May 31, 2013, Tim Samaras, his 24-year-old son Paul Samaras, and 45-year-old California native Carl Young died in the record wide EF3 multiple-vortex El Reno tornado. They were unable to escape along gravel roads as the funnel rapidly expanded to envelop them. Their Chevrolet Cobalt was caught by a subvortex, and Paul and Carl were ejected from the car. Tim was buckled in the passenger's seat, and was killed as the car was thrown approximately half a mile by the storm. Hinton resident Richard Henderson, who decided to follow the twister, lost his life in that same area. He snapped a picture of the storm from his cellular phone before it struck him. Several other storm chasers, including The Weather Channel's Mike Bettes, were also caught in the same sub-vortex but escaped with only minor injuries. Bettes and the Tornado Hunt crew were lifted up by the wedge tornado in their sport utility vehicle. That storm threw them two hundred yards off U.S. Route 81. The SUV was destroyed afterward. Bettes and his crew were later found and rescued by Reed Timmer and his SRV Dominator crew who were chasing for KFOR-TV Channel 4 in Oklahoma City with their storm chasers when they came upon the wrecked Great Tornado Hunt SUV. Four other people who were not involved with storm chasing also died in this tornado.
TWISTEX personnel
Tony Laubach; Mesonet Team Leader & Video Archival/Production, Meteorologist
Matt Grzych; Software & Systems Development, Atmospheric Scientist
Ed Grubb; Mobile Mesonet Navigator, Mechanical Guru
Dr. Bruce Lee; Mobile Mesonet Director, Atmospheric Scientist
Dr. Cathy Finley; Mobile Mesonet Co-Director, Atmospheric Scientist
Chris Karstens; Mesonet Team Leader & Software Development, ISU Atmospheric Sciences Ph.D. Student Ben McMillan; Mobile Mesonet Driver, Team Medic
Students from the Atmospheric Sciences Department at Iowa State University rotate shifts into the mesonet vehicles during the project.
Former TWISTEX personnel
Killed by the record breaking EF3 tornado in El Reno, Oklahoma: Tim Samaras; TWISTEX Director, scientist, engineer Paul Samaras; videographer Carl Young; Probe Driver, meteorologist
Tornado core sampling
Several hardened instruments will be deployed in paths of tornadoes to collect the following datasets: atmospheric pressure, temperature, humidity, wind speed and direction, and visualization for accurate debris/hydrometeor velocities and for verification of the tornado-relative location of the in situ sampling.
The thermodynamic probes are called Hardened In-situ Tornado Pressure Recorders (HITPR). All of the hardened instrumentation can collect/store the datasets. Measurements are recorded at 10 samples/second, and stored on non-volatile flash cards.