Between 75 and 105 millimetres of rain is in Calgary’s weather forecast this weekend, and that has the city on alert for flood risk.
Environment Canada is predicting rain on Friday, Saturday and Sunday, and the Weather Network forecast model is suggesting between 50 and 75 mm could fall on Saturday alone.
A special weather statement was issued by Environment Canada early Thursday, saying that general precipitation will range between 50 and 100 mm by Sunday, “however some areas, especially along the southern foothills, could see between 100-200 mm.” The weather is also expected to come with gusty winds.
The City of Calgary said it has its eyes on the skies and they are prepared.
“The forecasted precipitation is welcome, given the seasonally dry conditions we were experiencing; however, the precipitation expected is intense and widespread enough to prompt preparatory, precautionary flood readiness actions,” read an email from the City of Calgary.
They noted that with the Springbank Off-stream Reservoir now in operation, 70 per cent of Calgary’s flood damage potential is eliminated. That’s up from 55 per cent prior to the reservoir’s opening.
The City of Calgary did say that citizens can expect to see both the Bow and Elbow Rivers swell, though they don’t expect significant river flooding.
“Calgarians will notice that the water level in the Glenmore Reservoir is decreasing, to make room to store river water, so that as the river rises, we can limit the flow released downstream of the dam,” the City’s response read.
Earlier this year, the City said it would be keeping the Glenmore Reservoir at higher-than-normal levels to ensure there was an adequate water supply during dry summer months.
The City of Calgary said they’re monitoring the weather forecast, particularly around forecast precipitation amounts, and how that moisture falls (rain versus snow at higher elevations). The special weather statement said that the rain will turn to snow in higher elevations as temperatures cool in the mountains on Friday.
The City encourages citizens to keep an eye out for high-streamflow or rainfall advisories. If needed, the City of Calgary will provide information through the media, social media and via their website.
Right now, the Bow River upstream in Cochrane is showing a higher water level compared with earlier this year, but on the lower end of a band of flow rates for this time of year, according to the province’s streamflow monitoring system. The Elbow River is flowing below average through Calgary right now.
Stay vigilant with changing weather
The City of Calgary said that pathways may be closed under bridges and there could be localized flooding of park areas. They caution citizens from approaching high-flowing creeks and rivers.
“High flows can create bank erosion and instability, and if a boating advisory is issued, being on the river is unsafe,” they said.
They also want property owners to take steps to be flood ready on their properties, ensuring that downspouts are extended away from homes. They can also ensure that storm drains are clear of debris, and citizens can contact the City if the storm drains don’t drain within 90 minutes.
The City said should there be flooding, particularly if more precipitation than forecast occurs, they are prepared. They stockpile materials for riverbank flooding and temporary barriers in case of localized flooding.
“Every spring, infrastructure such as water main valves, stormwater outfall gates, lift stations and pumps are prepared, tested or positioned for flood season, to reduce potential damages during a flood,” they said.
“We conduct training exercises to ensure we are ready to quickly respond to any emergency.”
