No significant flood risk for Calgary this spring: emergency officials

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Calgary doesn’t face a significant flood risk this year, according to city emergency officials.

Despite a mountain snowpack that’s an estimated 20 to 40 per cent larger than usual, forecasts for the upcoming months suggest there are currently no flooding concerns for the season, city council’s emergency management committee heard Tuesday.

“It has not started to melt quite yet, and so we’re not seeing the spring runoff starting and raising our river levels quite yet. But we are expecting that that will start to melt and raise our river levels to normal spring levels,” said Calgary Emergency Management Agency (CEMA) chief Sue Henry.

“At this time, the long-term forecast is looking drier and cooler going into the summer.”

However, it’s still too early to say definitively that Calgary will avoid flooding this year, Henry said. She said heavy rainfall, which can lead to river flooding, can’t be detected more than three to five days in advance, adding city officials are monitoring conditions that could present flood risks.

CEMA identifies 15 high-risk events for the city, four of which involve flooding: a “catastrophic” flooding event on the Bow or Elbow rivers, and a major dam breach on the same rivers.

A major dam breach is very rare, Henry said, while catastrophic flood events are unlikely — events estimated to happen about once every 100 years.

The massive flooding in southern Alberta in June 2013 was such an event, Henry said, but she stressed risk still remains.

“When we talk about a one-in-100 year flood, that doesn’t mean that since we had that flood in 2013 we shouldn’t expect to see that level for another 100 years,” she said.

Henry said a city emergency social services team could accommodate up to 0.5 per cent of Calgary’s total population in response to an evacuation. About 90,000 people were displaced by the 2013 floods.

The city agency estimated 55 per cent of Calgary’s flood damage risk has been mitigated since those 2013 floods. That number will climb to 70 per cent after the Springbank Off-stream Reservoir is operational; earlier this month, the province estimated that project would be completed in 2025.

Presenting to the council committee Tuesday, Brenda Fioretti with the Alberta Emergency Management Agency said the province facilitates disaster recovery programs, which provide financial aid for insurance losses in a disaster.

Floods caused by rainfall have to measure at least at the one-in-25-year level in urban areas to qualify as extraordinary events eligible for the aid, she said.

The program has paid out for at least one disaster across Alberta each year since 1999, with its average annual cost since 2010 totalling $240 million.

“The cost and frequency of disasters in Alberta is increasing,” Fioretti said. “In terms of disaster insurance payouts, six of the top 10 costliest Canadian natural disasters have occurred in Alberta.”

jherring@postmedia.com

Twitter: @jasonfherring