It was a trip down Tornado Alley these Manitoba storm-chasers will never forget.
The University of Manitoba offers a class in storm-chasing every summer, now open to the public, which includes the irresistible lure of a trip to Tornado Alley, the name given to the route storms track through midwestern American states, like Oklahoma, with predictable and devastating effects every summer.
The tornado this time was in South Dakota outside a town called Erwin, 60 kilometres southwest of Watertown.
We asked one of the experts, John Hanesiak -- a U of M professor of environment and geography -- what happened. Here are excerpts from his email response.
"It was the first day of our University of Manitoba's storm-chase course field trip... And a long drive for the first day out of Winnipeg." he wrote.
Ahead, four vehicles out of Winnipeg spotted a cluster of atmospheric elements with all the right ingredients: Cool air aloft, churning winds and acres of farm crops on the ground below.
It was the U of M's storm-chase course's very first tornado and it will forever be engrained in all of our memories for the rest of our lives.
Crops, it turns out, sweat moisture that winds whip up to spit out fingers of fate.
The Manitoba crew got into position.
"The road network... was not the greatest and there were little options for emergency exit routes. There was a large line of storms behind, to the west of the storms we were watching, when suddenly, that line accelerated and caught up to the storm we were on and merged into the line," Hanesiak wrote.
Hanesiak's description of the single thunderhead turning into a hydra is the join-up moment for storm-chasers. Here is power -- barely harnessed and totally unpredictable.
"With our storm now accelerating, and the updraft-rotation intensifying, we were suddenly in a precarious position with the road network being rather poor.
"We were caught in what is called the 'bear's cage' a (phenomenon) where the updraft and mescyclone are strongest, where our tornado ended up forming."
In the teeth of the storm, the group raced the wind as the tornado spun out of the hammer cloud above them.
"We were running from the storm at this point, and only a few of us managed to get photos and video of the tornado. In fact, we think there were multiple funnels and touchdowns as we were running." Hanesiak wrote.
"My only personal vision of the tornado was in the rear-view mirror... The debris cloud was very dark and fairly wide at the very bottom. It filled half the rear view mirror."
The roads weren't helping them outrun the twister, and they were moving so fast the photos they hoped to get were never captured.
"The roads unfortunately took us deeper into the bear's cage...
"The tornado was likely only hundreds of metres away... to our right. It was tall; a thin tornado, maybe EF-1.
"Three of our vehicles stayed together and hunkered down in a farmer's driveway that dipped down off the main road," Hanesiak wrote.
They didn't seek the deepest part of the ditch, in case there was flash flooding. Later on, there was.
One vehicle in the group got separated.
"The fourth vehicle ended up going into the town of Erwin and parked beside a church on the downwind side. They now had God on their side," Hanesiak quipped. "Or at least they hoped."
All four vehicles felt the thrust from strong winds, driving rain and nickel-sized hail.
"The fourth van had a very large tree crash right in front of them, just as they were moving away from the church."
Afterward, they tracked a trail of minor damage to buildings and trees in town to a restaurant. Steak is a quirky custom after storm chasers spot a tornado. No one was hurt.