It is set to be a wet weekend across southern Alberta, with warnings about high water levels in the Bow River and the potential for flooding in Banff National Park.

Saturday night could see some thunderstorm activity, with heavier rains falling Sunday through Monday and into Tuesday, said Christy Climenhaga, scientist with Environment and Climate Change Canada. Temperatures will also drop.

Calgary could see between 50 to 75 millimetres, while areas west of the city could see upwards of 100 millimetres, Climenhaga said.

“It’s hard to say with certainty exactly where and exactly how much we will see there, but that risk is there for those regions,” she said.

Bow River advisory

A high stream-flow advisory has been issued for the Bow River, starting upstream of the Town of Banff down to the Ghost Reservoir, about 50 kilometres west of Calgary.

WATCH | Flood mitigation work beginning in Banff amid high stream-flow advisory:

Flood mitigation work beginning in Banff amid high stream-flow advisory

A high stream-flow advisory was issued for the Bow River upstream of Banff down to Ghost Reservoir, and a flood watch is in effect for areas near Lake Louise.

RCMP say rivers in Banff are flowing at higher-than-normal levels due to a stretch of warm weather in recent days melting the high snowpack. 

That, combined with the rain forecasted over the weekend, could cause “nuisance flooding,” the RCMP said. Some trails in the area could be closed this weekend if flooding occurs, and visitors are warned to stay back from the edges of rivers and streams. 

The Town of Canmore is urging extreme caution near the Bow River, especially by children and pets. It is recommending people stay off embankments, and boats stay off the river. 

Calgary issues boating advisory

The Calgary Fire Department issued an advisory Friday against boating on the Bow and Elbow.

The city is not expecting any overbank flooding, but says localized flooding along the rivers is possible.

Several pathways under bridges have been closed, including the Centre Street Bridge underpass pathways along the Bow, and the Elbow River pathway under Scollen Bridge on 25th Avenue S.W. More pathways could be closed if river levels continue to rise.

Frank Frigo, who heads environmental management at the City of Calgary, says water in the Glenmore Reservoir has been drawn down by about a metre to add more storage capacity.

Major flooding not expected

On Friday, the Bow River in Banff was flowing at 300 cubic metres per second — more than double its normal flow at this time of year, according to John Pomeroy, the director of the Global Water Futures Observatories at the University of Saskatchewan, who is based in Canmore.

By comparison, it was flowing at more than 430 cubic metres per second in the 2013 flooding.

Pomeroy does not expect a replay of 2013, not only due to the weather conditions but also the lessons learned from that significant flooding.

“But the important thing is for people making travel plans and things like that: expect the unexpected,” he said.

Calgary Mayor Jeromy Farkas said it’s natural if Calgarians feel anxiety around major rain events after the 2013 floods.

But he said the city, with the help of the provincial and federal governments, has made major flood mitigation investments since then, to the tune of $1.3 billion. And he says city staff are working to keep residents informed.

“It’s important to emphasize that these conditions can change on a dime, so we’re going to be as proactive as possible to inform Calgarians about what we know,” said Farkas.