At the last minute on Monday, the province reduced the level of flood threat in the mountain region from a warning to a surveillance.
A warning means that a flood seems imminent, while a warning means that conditions are favorable for it to occur.
BANFF
While considered a positive development, Banff fire chief Silvio Adamo said he has not changed the city’s plans to protect the river’s banks.
“What we’ve learned from 2013 is to be prepared and deploy soon,” Adamo said. “So even with a discount to see, the forecast figures we’re seeing still justify taking that kind of precaution. And we’d rather be preventive than reactive.”
Banff firefighters spent most of Monday unfolding long orange tubes known as “Tiger Dams” along the riverbank.
They can be filled with water to create a wall almost 1.2 meters (four feet) high to prevent flooding. In addition, the city of Banff warned residents living in the lower areas of the city in a complex along Birch Ave. that they were prepared to evacuate if the river rises.
“We went door to door yesterday afternoon and touched the base with the 130 units of these two complexes, (on Birch Ave) just to send them messages of readiness,” Adamo said.
Banff has also closed some trails near the river and advises residents and tourists to avoid their shores.
CANMORE
The city of Canmore is monitoring groundwater levels, steep streams and the Bow River. City officials said problems will be expected in low-lying areas if the city receives more than 50 millimeters of rain.
Existing flood mitigation work along Cougar Creek is expected to ensure that the flow in the canal is maintained.
The road under the Bow River Bridge at Canmore was closed last week. Additional trails will be closed at Canmore along the Bow River if rising water levels pose a safety risk.
John Pomeroy, a hydrologist at the University of Saskatchewan who lives in Canmore, said there are some key differences between this weather event and the one that caused the 2013 floods.
He mainly cited the temperature at higher altitudes.
“The expected 150 millimeters of rainfall is a lot, but in the high mountains, a lot of it could fall like snow. This will make a big difference in the ability of this system to generate flooding.” said Pomeroy.
“The mantle of snow that accumulates in the mountains will stop the melting of the snow that is taking place. It has been releasing between 40 and 50 millimeters of water a day, in the high mountains. This will stop it and, instead, it will accumulate the snow cover, and then melt more slowly over the next few days. “
But Pomeroy warned that the difference between a layer of snow in the building and a slow melt and a rapid downpour that caused flooding was only a matter of a few degrees.
“If the weather warms up at high altitudes, just a couple of degrees, then we would have rain on snow instead of snow forming in the high mountains,” Pomeroy said.
“Rain on the snow is the worst safe scenario. That’s what happened in British Columbia in the Fraser Valley in November. And it happened in the mountains over Calgary in 2013.”
Although the Bow River flows through Canmore, most of the 2013 floods were generated from Cougar Creek, which has since undergone massive repairs.
Monday was without water, which gave many Canmore residents a sense of optimism.
“I’m pretty sure you know, it must be pretty bad for them to break them now that you know. although personally it is not. too worried he knows the memories of 2013 are still strong for many in the mountain town.
“I think a lot of people are pretty anxious when it starts to rain like that, because last time they predicted about the same amount of rain, and it turned out to be three times. You know, bum, it all came down to the valley.”
EXSHAW
In 2013, Exshaw residents were shocked when three streams overflowed its banks and submerged many of the 449-person community homes.
Since then, Bighorn City District has improved all three streams with high levels of flood protection. Both Exshaw Creek and Jura Creek are able to withstand a flood of one in 500 years, while Heart Creek has been upgraded to one in 300 years.
MD CAO Robert Ellis was optimistic that Exshaw would be spared any major flooding this year.
“The forecast we have heard, the amount of water does not even come close to the precipitation we received in 2013. And with the amount of mitigation we have done for the streams involved, this obviously affected Bighorn’s MD , we don’t see this kind of flooding on the ground during this event, “said Ellis, who said that while groundwater floods are unlikely to have a high risk of groundwater flooding in some parts of the community. .
“We’ve always had some flooding east of Exshaw. It’s one of the lowest points in the community. Water comes in and seeps into basements. We had an event in 2020, where the water increased with the pressure on the Bow River and our aquifer filled up. I don’t know if we’ll see the same kind of thing. But the basements will probably be wet. “
East Exshaw resident Kelly Suchan is one of the residents whose basement was flooded in 2020, even after the creek repair was completed.
On Monday, he was installing five tank pumps in his home to try to prevent this year’s flood damage.
“I’d rather do this now than two or three in the morning. So I’ll get ready,” Suchan said.
“If it happens, it happens. If it doesn’t go well, just wrap it up and keep it and wait until next year.”