Calgary will stay in a State of Local Emergency as it watches a second system building west of the city, officials said Thursday.
A combination of weather factors could make the flood risk with the next system much greater, said Francois Bouchart, director of Water Resources with the City of Calgary.
Bouchart said the second system building in the Kananaskis region west of the city, could produce between 50mm and 100mm of rain in the coming days. But, what saved the city from significant flood problems in the last weather event, could come back to worsen the next system, even though rainfall amounts are lower, Bouchart said.
Snowfall accounted for roughly 25mm of precipitation in the last storm. That means it didn’t translate into river flow.
“The importance here is that with the snow we add more moisture within the catchment, within the watershed,” Bouchart said.
“We are also now dealing with a watershed where the ground is saturated with water and therefore a smaller event will result in a more significant flow response from the river.
Bouchart estimated that if the next system produces 70mm of rain, the Bow River could see flow rates of up to 1,200 m3/s. To compare, the 2013 flood produced Bow River flow rates of 2,400 m3/s.
“I do want to stress that these are early days in terms of this next system,” he said.
“It takes time for these systems to build up and to indicate whether or not… the system is going to start wrapping around the Eastern Slopes.”
Berm to remain
Calgary Mayor Jyoti Gondek said the Hillhurst Sunnyside berm will remain in place. At least until the risk from the next system subsides. That could be sometime next week.
“That system is something that water resources is keeping an eye on and something that’s related to that is the berm that we put in place on Memorial Drive,” the mayor said.
The City will be making modifications to the berm, allowing one lane of traffic in each direction.
The mayor said the berm cost $115,000 to build and took 18 hours to erect. She added that it was protecting $53 million worth of property.
Calgary Emergency Management Agency Chief Sue Henry said the berm will allow for local traffic and emergency vehicles to access the area.
She said work on the berm would likely be complete Friday morning.
“The barrier system will remain in place for now while we monitor the next weather system,” she said.
Henry also said that most parks have reopened, with the exception of Rideau Park. Boating advisories are still in place on the Bow and Elbow Rivers.
Calgary 311 recorded 1,008 tree fall calls since Monday and they’re still working on some of those calls.
Henry asked that Calgarians remain vigilant.
“We are still in flood season and the forecasts and the river conditions can change quickly and with little warning,” she said.
Calgarians can stay informed with the latest information by visiting Calgary.ca/flood.