A record-setting hailstorm in Alberta was a bonanza for scientific hail chasers

This summer a terrifying and potentially deadly hail storm in Alberta saw softball-sized chunks of ice smashing through vehicle windows. But it was record-breaking scientific bonanza for a group of storm-chasing researchers.

Researchers with the Northern Hail Project (NHP) sent a team of hail chasers to Alberta's infamous "hail alley." It was a pilot study to collect difficult to obtain on-the-ground data that they hope will improve our ability to forecast hail. 

Alberta's hail alley stretches roughly from Rocky Mountain House in the north to about High River, south of Calgary. The conditions there in the mid-summer are ripe for big hail storms.

"We can have a good idea on a given day where there are going to be potentially severe storms, and that some of those storms might produce hail, but the devil's in the details," said Julian Brimelow, the executive director of the NHP, which is based out of Western University in Ontario.

He said nobody on that August 1 holiday Monday was expecting record-breaking-sized hail. The forecast called for golf ball-sized hail for the region, not softball-sized. 

"Radar wasn't suggesting particularly large hail in the area where that record hailstone was found," said Brimelow, "so that right there points to a big problem we have even with the sophisticated state-of-the-art radars that we have now in Canada." 

That Monday started off like any other for the hail chasers. The lead of the NHP field operations team, Francis Lavigne-Theriault, wrote in an email that the team was out tracking several developing storms until later in the day when they turned their attention to one particularly ominous-looking supercell storm capable of unleashing destructive winds, tornadoes and hail.

Each time the hail chasers stopped to collect hailstones, they were finding bigger and bigger ones. 

"It wasn't your typical hailstorm where there's a lot of smaller hail," said Lavigne-Theriault. 

Instead they saw fewer hailstones on the ground than they were used to, but the ones they did find were a lot bigger. 

"They were all massive," said Lavigne-Theriault. "That's how we knew we had something."

Probably 20, 30 seconds later, the back window gets destroyed and you just start seeing windows — one by one — get blown out.- Gilbran Marquez

For motorists in the storm's path travelling along the Queen Elizabeth II Highway, their first sign of danger came with a tornado warning.

Gilbran Marquez was driving north with a couple of friends when, within 20 minutes, their sunny sky started to darken and look more intimidating as the storm intensified and the wind picked up.

In an interview with CBC Radio, Marquez said what made them finally pull over was the sight of one softball-sized hailstone that remained fully intact after bouncing off the highway into the ditch.

"Probably 20, 30 seconds later, the back window gets destroyed and you just start seeing windows — one by one — get blown out.... And these things just sound horrible hitting the roof just cratering above me as I look up."

According to the RCMP, the hail storm damaged more than 70 vehicles along the highway that day. Fortunately, nobody was seriously injured.

The researchers collected seven bags of large hailstones that day, including a record-breaking one weighing in at 292.7 grams and 12.3 centimetres in diameter. 

Their plan is to use this off-season time to study the hail they collected. The team will also study data from satellite and radar systems, remote camera recordings, and the styrofoam impact mats they deployed, which can provide information on size and number of hailstones. All this will go into forecasting models to improve our ability to predict destructive storms like this one.

Next year Brimelow said their plan is to expand their field research to another Canadian hail hotspot in Saskatchewan.

Produced and written by Sonya Buyting.