Several days of unseasonably warm temperatures combined with a forecast of up to 100 millimetres of rain this weekend have communities in southern and central Alberta preparing for the possibility of flooding.
The forecast high for Calgary on Friday is 27 C — about 10 degrees above normal — and while the mercury is expected to fall to around 10 C by Sunday, Environment Canada is forecasting up to 100 millimetres of rain beginning Saturday night and continuing into the early part of next week.
It comes as a rapid mountain snowpack melt is leading to rising rivers.
2:03
Officials on flood watch in Rockies
A flood watch has been issued for the Pipestone and Bow Rivers near Lake Louise (orange area) and a high streamflow advisory has been issued for the Bow River through Banff and downstream to the Ghost Reservoir.
Source: Alberta Rivers
The rising water levels have already prompted a flood watch for the Pipestone River and the Bow River near Lake Louise, and a high streamflow advisory to be issued for the Bow River in the Banff area, downstream to the Ghost Reservoir — which is about 60 kilometres west of Calgary.
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In Lake Louise, some low-lying areas and trails have already been flooded by the rising waters and emergency officials in the town of Banff have been deploying temporary flood barriers in spots that could be affected.
The town of Banff is preparing for the possibility of flooding by setting up temporary flood barriers called a “Tiger Dam.”
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The risk of flooding has also been exacerbated this year by heavier-than-normal snowpack in the mountains.
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With large amounts of snow still present at higher elevations, Parks Canada warns that unseasonably warm temperatures, combined with heavy rains also increases the danger of avalanches — so anyone heading into the backcountry is advised to avoid avalanche-prone areas.
Parks Canada warns that some trails and day use areas in low-lying areas of Banff National Park may also be subject to temporary closures.
Source: Facebook/BanffNP
In Calgary, emergency officials are also keeping a close eye on the Bow and Elbow Rivers.
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The city issued a boating advisory on Friday afternoon advising against all boating and other activities on both the Bow and Elbow Rivers effective immediately.
With the water levels expected to continue to rise over the weekend, the city warns pathway and underpass closures may be put in place too.
While the city says no widespread flooding is expected at this time, with between 50 and 90 millimetres of rain forecasted for Calgary, rivers are expected to rise.
As a result, residents are being asked to exercise caution around the rivers and in low-lying areas.
“We understand that Nature is in the driving seat and we’ve learned a lot of lessons since 2013 so we’re approaching the event with caution,” said Frank Frigo manager of environmental management for the City of Calgary.
“Calgarians will (also) notice that the water level in the Glenmore Reservoir has been drawn down by about a meter from where it was over the last couple of days — and that is one of the additional precautions to allow more storage to be able to slow down any large flows that might occur early next weekend.”
The Elbow River in Mission is one of the areas the city of Calgary will be keeping a close eye on over the next few days.
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Homeowners are being advised to make sure eavestroughs and extensions are directed well away from homes and garages, to help keep community storm drains clear of debris and report any pooling water to 311.
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“When it comes this hard, this fast, we could see an oversaturation and that doesn’t allow enough time for the soil, especially for areas that have been so dry and are potentially hydrophobic — it doesn’t allows that moisture to soak in fast enough, if at all,” said Global News meteorologist Tiffany Lizée.
“So we’re going to see a lot of sitting water and as that continues to rise, it could definitely cause localized flooding for some communities, especially those heavier amounts that we’re expecting in the southwest, in the Lethbridge area, and to the west of Lethbridge.”
The city of Lethbridge says, while the water levels in the Old Man River are “a little bit” high they are well within normal for this time of year.
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The city of Lethbridge is warning residents to prepare for a “significant downfall” of rain in the coming days and has provided a list of tips for residents on the city website, including “do not drive through large puddles” and “be careful in the coulees” as trails can be slippery and dangerous when it rains.
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Mark Svenson, environment manager for the city of Lethbridge said, while the Old Man River does look higher than normal, “the flows are within that normal range, well within the normal range.”
“However, it can change and is changing daily, so keep an eye on it — it can come up rather quickly,” said Svenson.
“Keep eyes on your surroundings so that you know. Where you can go to be safe if you need to escape.”
A special weather statement, issued by Environment Canada, forecasts the rain to begin falling Saturday night and continue through Tuesday before easing off Tuesday night and into Wednesday.
While the precipitation is forecast to fall as rain at lower elevations, Environment Canada said higher elevations, in the mountains, could get up to 20 centimetres of snow.
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Calgary flood season underway with new Sunnyside mitigation
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