I knew we couldn't stop. The rain was so heavy I couldn't see the Bravada in front of me, so we just kept driving through the field," says Jeff Bernard, describing how his Explorer bounced over a muddy Texas wheat field, following tractor ruts, and how hard he pushed it to escape an oncoming tornado.

Bernard, a 39-year-old casino manager, was on vacation in Tornado Alley, sightseeing the notorious weather. Early each summer, hundreds of tourists road trip to the Texas and Oklahoma panhandles, hoping to catch a glimpse of one of the 70 or so significant tornadoes that drop from massive storm systems besieging the region. Bernard was following a professional weather photography crew led by veteran storm chaser Warren Faidley (in a gloss-black Explorer) and electronic-systems developer Phil Henry (in a black Oldsmobile Bravada). Both of these machines had four-wheel drive-and needed it.

"I just kept feathering the throttle and the Bravada kept moving," says Henry, who was testing out a rooftop satellite antenna on his Bravada to receive real-time-weather radar images. The hailstorm approaching this group of SUVs cut visibility, and there could be a killer twister bearing down on them. "I was kicking myself for not getting the Explorer with four-wheel drive," Bernard continues. "But I live in Las Vegas, and I figured I'd never use it."

SUVs are the chaser's vehicles of choice for several reasons: The chasers live out of them for up to one month during tornado season and need accessible room for camera and video gear. Tall ground clearance and four-wheel drive are necessary when storms flood roads. On rare occasions, chasers may have to bushwhack a road through a field and need the durability of a truck.