CALGARY, AB, CANADA — The skies were still calm when the first wind storm alert went out midday Saturday.

As early-bird Christmas shoppers took advantage of the pleasant afternoon to chase down deals, members of Calgary’s special emergency response team quietly began mobilizing, too.

A new wind warning system designed to predict Calgary’s gustiest storms was predicting Category 1, or hurricane force, gales could sweep through downtown towers the next day.

By Sunday morning, the storm hit.

Trees crashed down, windows shattered and power lines collapsed as the storm blew through the city, shuttering the downtown, swamping emergency responders with calls and prompting the city to enact its Municipal Emergency Response Plan.

When the winds died down and the damage tallying began, the city’s emergency response boss breathed a sigh of relief.

Sunday’s storm was bad, but it could have been much worse, said Bruce Burrell, director of the Calgary Emergency Management Agency.

“We’re the luckiest city in the world,” said Burrell, who is also fire chief.

“It’s incredibly hard to believe that given the amount of debris that was on the streets and the amount of pieces of glass and shards of glass that were all over the downtown area (Sunday) evening when I went down there and took a look around, that we did not have more significant injuries.”

The city is lauding Sunday’s response to the storm a success. Part of that’s due to the early warning weather forecasting alert system.

The city implemented the forecasting technology after a freak windstorm that had a far more tragic ending. In August 2009 three-year-old Michelle Krsek was killed by a steel bundle that plummeted from a downtown work site during a gusty storm.

“Because of that, we, with the industry, have made some drastic adjustments in what we consider to be safe, and we’ve seen the results of that . . . this last weekend that demonstrates it is valuable,” said Kevin Griffiths, the City of Calgary’s chief building official.

The system is in place at three Calgary sites and set to become mandatory for new downtown towers in the new year. It forecasts 48 hours ahead, based on how the wind is expected to affect specific building locations.

On Saturday morning the system indicated high winds were going to hit the downtown, Griffiths said.

The city then informed the emergency response group, which began monitoring the sky.

Within hours Saturday afternoon, Environment Canada put out an official warning.

As breezes picked up Sunday morning, a “fair bit of monitoring” was underway, Burrell said.

It was 11 a.m. when the Calgary Fire Department became overwhelmed. It was only able to send one fire truck to each call. An hour later fire crews had 178 unanswered calls in a priority queue.

At 1:05 p.m. the city enacted its Municipal Emergency Response Plan.

“By roughly 2 p.m. (Sunday) we were well aware of the magnitude of the event; what it was doing throughout the municipality,” said Burrell.

“We had some preliminary mapping that showed us it was a widespread event, all the way from Stoney Trail, where the truck flipped over, right down all the way to the deep south end of the city.

“We tracked the calls, we tracked the events. Everybody worked incredibly well together.”

At the height of the storm the city’s 311 and 911 call centres handled four days’ worth of calls within just five hours.

Sunday’s blast was no ordinary chinook.

An intense, low-pressure system moving in from the northern Pacific, the warm temperatures settled across southern Alberta and the enhanced wind flow from the downslope of the Rockies, smashing together to cook up the windstorm, said Environment Canada meteorologist Bill McMurtry.

“It was much more than just a chinook,” he said.

Environment Canada put out an official wind warning around 3:30 p.m. Saturday for Sunday’s event.

Calgary clocked gusts of 91 km/h at the airport, though the gales were much higher at higher elevations, such as office towers.

When the wind finally calmed, four assessment teams branched out downtown to map the damage and plan where to focus cleanup crews.

Overnight, roughly 100 city staff moved street by street cleaning up the downtown. Road crews picked up large pieces of debris and tossed it into trucks to be taken to landfills, sweepers tidied the streets as best as possible.

By 4 a.m. Monday much of the core was ready to reopen for the work week.

The morning commute remained a headache. It wasn’t until late Monday afternoon that C-Train service in the downtown was restored.

Hard-hit homeowners spent much of the day recording damage and connecting with insurance agents.

The city deactivated the emergency plan at 3:55 p.m. Monday.

The city’s costs are likely to reach seven figures, Burrell predicted, though it will likely take weeks to determine the tab.

All told, Calgary emerged from the storm “pretty darn lucky,” Burrell said.

“It was one of those situations that worked out very, very, very well and we’re pleased there were no significant injuries.”