Tornado Intercept Vehicle

TIV 1

The Tornado Intercept Vehicle 1 (TIV 1) is a heavily modified 1997 Ford F-Super Duty cab & chassis truck used as a storm chasing platform and built by Sean Casey. This heavily armored vehicle can drive into a weak to relatively strong tornado (EF0 to EF3) to film it and take measurements. Work began on the TIV in 2003 and took around eight months to finish, at a total cost of around US$81,000. TIV's armored shell consists of 1/8–1/4 inch steel plate welded to a two inch square steel tubing frame. The windows are bullet resistant polycarbonate, measuring 1.5 in (38 mm) thick on the windshield and 0.5 in (13 mm) thick on the sides. The TIV weighs approximately 14,000 lb (6,400 kg) fully loaded and is powered by a 7.3 litre Ford Powerstroke turbocharged diesel engine manufactured by Navistar-International, otherwise known as the International T444E. The vehicle's speed was limited by the factory Ford PCM, giving it a top speed of 100 mph (160 km/h). The TIV has a fuel capacity of 60 US gallons (230 L), giving it a range of around 500 miles (800 km). The TIV is featured in a series called Storm Chasers which began airing on the Discovery Channel in October 2007. TIV was succeeded in 2008 by TIV 2, but returned to service to finish out the 2008 storm chasing season after TIV 2 suffered mechanical problems. In a June 2011 interview with NPR's All Things Considered, Casey said that TIV is still in service and is designated as the backup vehicle in the event TIV 2 breaks down during a shoot.

TIV 2

Casey and his team developed and built the second Tornado Intercept Vehicle, dubbed TIV 2, to be featured in their next IMAX movie and the Storm Chasers series. Work began in September 2007 by forty welding students at the Great Plains Technology Center in Lawton, Oklahoma and was completed in time for the 2008 tornado chase season. TIV 2 was designed to address some of the problems experienced with the original TIV, namely its low ground clearance, lack of four-wheel drive, and low top speed. It is based on a Dodge Ram 3500 that was strengthened and converted to six-wheel drive by adding a third axle. After season two the six-wheel drive system was modified to four-wheel drive. It is powered by a 6.7-liter Cummins turbo charged Diesel engine, modified with propane and water injection to produce 625 horsepower (466 kW). This gives TIV 2 an estimated top speed of over 100 mph (160 km/h). Its fuel capacity is 95 US gallons (360 L), giving TIV 2 an approximate range of 750 miles (1,210 km). The body of TIV 2 is constructed of a 1/8-inch steel skin welded over a 2 in (51 mm) square tubing steel frame. The windows in TIV 2 are all bullet-resistant 1.63 in (41 mm) interlayered polycarbonate sheets and tempered glass. TIV 2 also features an IMAX filming turret similar to the one on the original TIV. The original TIV's somewhat cumbersome hydraulic claws were not used on TIV 2 in favor of six hydraulic skirts that drop down to deflect wind over the TIV to stabilize it and protect the underside from debris, and four hydraulically operated anchoring spikes.

TIV 2 debuted on the second season of Storm Chasers, which began airing on the Discovery Channel in October 2008. Its initial performance did not go well, as it was plagued by mechanical failures, including several broken axles, which forced Casey to abandon TIV 2 and return to chasing in the original TIV until TIV 2's issues could be resolved. Although Casey hoped he would be back in TIV 2 before the end of the season, repairs and modifications on TIV 2 took longer than expected and Casey was shown on Storm Chasers ending the season in the original TIV.

In the fall of 2008, TIV 2 received several modifications, mostly focused on reducing the vehicle's 16,500 lb (7,500 kg) weight. To achieve this, certain less crucial areas of TIV 2's armor were converted from steel to aluminum while more vital areas were reinforced with supplemental composite armor consisting of thin layers of steel, Kevlar, polycarbonate, and rubber. In all, the weight reduction measures brought TIV 2's weight down to 14,300 lb (6,500 kg). The safety systems were also improved, with the three front wind skirts being consolidated into one and new hydraulic stabilizing spikes to further increase stability in high winds. Other modifications included additional doors that provided every seat position with an exit (wind skirts up or down), and a redesigned IMAX turret with 50% more windows. The third axle was disconnected from the drive train, thus changing TIV2 to 6×4 from its 6×6 design. The third axle now acts as a brace for the vehicle's weight.

The TIV 2 appeared again in the fourth season of Storm Chasers, and also in an episode of another Discovery Channel series, Mythbusters, wherein both the TIV 2 and the SRV Dominator vehicle operated by Reed Timmer of TornadoVideos.Net were tested to determine their endurance to storm-force winds by being parked behind a Boeing 747 with the engines at full throttle. When tested at a wind speed of 160 mph (260 km/h), the TIV 2 had the driver's door pulled open, though this was due to human error, as Casey forgot to lock the door prior to the test. When tested again at 250 mph (400 km/h) (equivalent to an EF5 tornado), the TIV 2 suffered no ill effects other than the anchoring spikes being slightly bent; the Dominator ended up being blown approximately 50 feet (15 m), although it remained upright.

In 2011, a siren was added to the vehicle to allow the TIV 2 to act as a mobile warning system for civilians in the path of incoming tornadoes, after several incidents earlier that year where the TIV team was unable to effectively warn locals of the imminent danger of the tornadoes they were tracking, especially during the 2011 Super Outbreak. On April 27, 2011, the TIV 2 team intercepted an EF4 tornado that hit near Enterprise, Mississippi, while not in the path but 200 yards from it, it was the first tornado he shot with his new 3-Dimensional IMAX camera.

Casey removed the rear flap in early 2012 and built a new set of two hydraulic spikes that go into the ground during an intercept.

On May 27, 2013, TIV 2 intercepted a large tornado near Smith Center, Kansas. The vehicle was struck by large debris from a nearby farm and suffered damage to the roof-mounted anemometer and at least two breaches of the crew compartment when the roof hatch and one of the doors were compromised. Before the anemometer was disabled, it recorded winds of 150 to 175 mph (241 to 282 km/h), placing the tornado in the EF3 to EF4 range.

Instrumentation

Although primarily designed to shoot film from near or within tornadoes, the TIV's have at times been outfitted with meteorological instrumentation atop masts to complement the Doppler on Wheels (DOW) radar trucks of the Center for Severe Weather Research run by atmospheric scientist and inventor Joshua Wurman.