More chasers risking lives on the roads

The deaths of four storm chasers in car crashes over the past two weeks have underscored the dangers of pursuing severe weather events as more people clog back roads and highways searching for a glimpse of a lightning bolt or tornado, meteorologists and chasers say.

Martha Llanos Rodriguez of Mexico City died on Thursday when a semitrailer ploughed into her vehicle from behind on Interstate 90 in southwestern Minnesota after the car’s driver had stopped because of downed power lines on the road.

More people were hopping into their cars and racing off after storms, jamming up roads, running stop signs and paying more attention to the sky than traffic, said Marshall Shepherd, director of the atmospheric sciences programme at the University of Georgia.

‘‘There is such a volume of chasers out there on some storms sometimes that it creates potential traffic and other hazards,’’ Shepherd said.

Popularised in the 1996 movie Twister, storm chasing involves pursuing severe weather events such as electrical storms and tornadoes, often in cars or on foot.

Some chasers are researchers looking to gather data, such as verifying computer models predicting storm behaviour. Some are looking to get in touch with nature. Others are photographers.

Others were just looking for a rush, said Greg Tripoli, an atmospheric and oceanic sciences professor at the University of Wisconsin-Madison who used to teach a class on storm chasing. ‘‘Seeing a tornado is a life-changing experience.’’

The storms themselves present dangers to inexperienced chasers who get too close. They can get hit by debris, struck by lightning, or worse. Tripoli said he had decided to stop teaching his storm-chaser class and taking students into the field in the early 1990s after university officials stopped insuring the trips.

Nature isn’t the only threat. Storm chasers spend long hours on the road, inviting fatigue. When they catch up to the storms, they can often keep their eyes on the skies instead of the road.