CALGARY -- The vicious storm that pounded Calgary with lightning, thunder and hail overnight Sunday saw wind speeds reach 107 km/h in some parts of the city.

In its wake, it left downed trees, broken windows and a swath of hail damage.

A confluence of systems that formed over northeastern B.C., the storm raced across Alberta faster than you could drive, said Environment Canada meteorologist Yvonne Bilan-Wallace.

After reaching Grande Prairie about 7 p.m., the storm arrived in the Calgary area just after 1 a.m., said Bilan-Wallace, covering the hundreds of kilometres in less than seven hours.

"It was moving about 90 km/h," she said.

"We're thinking this was the same type of situation we've been seeing a lot of this summer in Alberta, these gust fronts moving ahead of storms and causing brief periods of really intense wind.

"It's a very steady progression shooting down the backside of Alberta from Grande Prairie all the way to Calgary, taking a left-hand turn to Medicine Hat then going into Saskatchewan."

Colleen Christensen, 35, was asleep with her three children in their Delacour home when they were woken by sounds of windows smashing.

"It started with the sheet lightning then the wind started and within a minute there was about four inches of hail," she said.

Taking refuge in their basement, Christensen said she couldn't believe the intensity of the storm.

"You couldn't hear," she said. "To talk, we were in the same room and we were yelling at each other, it was that loud.

"I can honestly say I've never been more scared."

Lindy Pinel, 58, got up yesterday morning to find a huge tree knocked over directly across the street from her northwest home.

"It was huge," she said.

"It's kind of scary in the fact if it was a bit bigger it could have come through our windows."

Pinel said after seeing the downed tree, she was shocked to find the tomato plants in her backyard untouched.

"They're hanging just fine," she said.

Enmax said this is the largest storm it has seen in several months, with the overnight weather knocking out power at about 11,500 homes.

"It was right across the city -- every quadrant was impacted, some for just five minutes, some for four hours," said Enmax spokeswoman Doris Kaufmann.

The electricity provider brought on extra staff to answer phone calls from customers who woke up to a power outage in their homes, as well as go to impacted neighbourhoods and fix the problems.

"It was definitely the biggest storm of the summer -- it was pretty fast and furious," said Kaufmann.

It was the second major wind storm to roll through Calgary in as many days.

dave.dormer@sunmedia.ca