[5][6] He also experienced a hailstorm at the age of 13, which he called his "first storm chase", and resulted in his family's video camera being destroyed after attempting to capture it.
[6][8][13] While as a freshman at the University of Oklahoma, Timmer began storm chasing on May 3, 1999, where he encountered the Bridge Creek–Moore tornado, forcing him and three friends to take shelter under a highway overpass.
[16] While chasing a tornado a year later, the vehicle he was in lost control on an unpaved road and crashed into a sewage ditch, destroying his computer equipment, which was uninsured.
[17] In 2005, Timmer both chased a tornado east of Madelia, Minnesota, and Hurricane Katrina, with the latter event's flooding and storm surge he described as "intimidating".
[3][16] Additionally, he recorded a wind speed of 138.8 miles per hour (223.4 km/h), and the tornado, along with Timmer's chase, were included in a Storm Chasers episode.
[31] At the time, Timmer stated that the severe weather event was "hands down the most unforgettable day", while also describing the amount of tornadoes as "heartbreaking" and "overwhelming".
[36][37] A year later, in 2013, Timmer was injured after chasing the 2013 El Reno tornado for KFOR-TV, which ultimately killed four storm chasers, including Tim Samaras.
[16][35] While chasing a tornado outbreak associated with the October 2013 North American storm complex in Nebraska, Timmer was hospitalized after suffering a seizure as part of the KFOR-TV weather team.
[39] In the same year, Timmer constructed a third vehicle, the Dominator 3, modifying it from a 2013 Ford F-350 Super Duty pickup truck and weighing 11,000 pounds (5,000 kg).
[47] A year later, on May 16, 2017, Timmer deployed a weather probe inside an EF2 tornado southwest of Elk City, Oklahoma, which recorded a 360-degree video that received praise from AccuWeather affiliates.
[48] On January 23, 2018, Joel Taylor, one of Timmer's friends and the driver of the SRV Dominator vehicles, died from a drug overdose while on a cruise ship in San Juan, Puerto Rico.
[50] That same year, Timmer chased several natural disasters, including Hurricane Michael and a tornado in Federal, Wyoming, the latter event of which he recalled seeing "cows flying through the air".
[59][60] In 2022, while inside the eyewall of Hurricane Ian, Timmer filmed videos of the storm surge on Pine Island, which significantly damaged his vehicle, Dominator Fore, a modified 2018 Subaru Forester.