Incoming Alberta rains good for farmers, unlikely to cause major flooding says meteorologist

Alberta's seasonal 'June monsoon' is expected to be kicked into high gear Monday afternoon, with Environment Canada issuing warnings for heavy rainfall across much of southern Alberta, including Banff National Park, Kananaskis and Calgary. 

According to a special weather statement released early Sunday morning by Environment Canada, up to 100 mm of rain could fall by Wednesday, particularly on the foothills and eastern slopes of the Rocky Mountains. Current projections place the greatest rainfall amounts near Kananaskis. 

Kyle Brittain, the Alberta bureau chief for the Weather Network, said that while this week's prolonged rainfall could put the province past its typical monthly average for June, he doesn't expect it to cause severe flooding.

That's because historical dry conditions across the southern part of the province have led to a lower than average water table, said Brittain, leaving substantial room in the ground for moisture to be absorbed.

"[The] exceptional drought in southern Alberta, that actually gives us quite a good buffer against major flooding right now."

For Alberta farmers fearful that another drought like last year's could be repeated, Brittain said the heavy rainfall will bring some reassurance. 

"It looks like it's going to be a million-dollar rain for agricultural producers in southern Alberta. So it could actually really turn things around for our growing season."

Conditions which led to major flooding in parts of the province in 2013 were caused by both a higher amount of rainfall (over 300 mm in parts of the province) and concurrent storms close together, said Brittain. 

"If we have another big storm after this one, then we've got to start looking at flood concerns."

For now, Brittain said to expect some swollen rivers, with high water levels coming into Calgary from both the Bow and Elbow Rivers. 

On Sunday, the City of Calgary issued a boating advisory for the Elbow River, due to higher expected flow rates. According to the statement, Calgarians are advised against boating and all other watercraft activities on the Elbow River until conditions improve.

Frank Frigo, manager of watershed planning with the city's water resources department, said its preparing for the extended rainfall by lowering water levels at upstream reservoirs on the Bow River and at the Glenmore Reservoir to increase storage capacity in case of high flows.

While the city said it doesn't expect major flooding, it advised that Calgarians should still take precautions including directing rainwater away from homes by properly positioning downspouts, moving valuables out of basements in low-lying communities and exercising caution around riverbanks, especially on riverside pathways. 

According to city council's Emergency Management Committee, flood mitigation efforts in Calgary as of 2022 have reduced future potential flood damages by 55 per cent, or an average of $90 million per year.