Heavy rain has caused flooding in southern Alberta, where some roads are submerged and dozens of people in the town of High River have been forced from their riverside homes.

The Municipal District of Foothills, which includes High River, Redwood Meadows and Priddis, has declared a state of emergency.

In High River, officials closed the Highway 2A bridge over the Highwood River late Friday as a safety precaution after water rose to the bridge's bottom girders.

'It was like a giant bathtub was dumped on my house '— Flooding victim Juliana Halifax

People living in the High River subdivision of Wallaceville are under mandatory evacuation notice because of the rising water on the Highwood River, while residents in the Willow's Garden Apartments were under voluntary evacuation notice.

Fast-moving water, knee-high in places, flooded homes and streets in the neighbourhood of about 80 residents. A bridge was closed.

Volunteers rushed to sandbag Juliana and Dean Halifax's riverside home as water flooded into their basement and garage.

"It was like a giant bathtub was dumped on my house," she said.

The couple were refusing to leave their home on Friday morning, despite the mandatory evacuation notice.

"We are like a little island right now," she said. "If they have to take us – unfortunately at this point where I am at  – it is going to have to be by force."

Firefighters and RCMP officers helped with the evacuation, and a reception area for evacuees was set up at the Highwood High School.

Town officials have created a Facebook page to keep residents apprised of current conditions.

High River's acting mayor, Tim Whitford, said the problems began at 5:45 a.m. Friday when a dike failed, sending water into Wallaceville. By noon, emergency workers had managed to block the flow.

"We had a lot of resources on the ground in the daylight [Thursday], building barriers and dikes and getting things generally ready," he said. "And that has really paid off."

Other regions on alert

Much of southern Alberta is under a heavy rainfall warning, and Alberta Environment has listed warnings and watches for several river and streams.

"A slow moving Pacific disturbance which tracked across southern Alberta overnight will move into southern Saskatchewan this morning," Environment Canada officials said Friday. "This system has already generated up to 40 millimetres of rain in some areas with total accumulations expected to approach or exceed 50 millimetres by this afternoon."

In Calgary, high water on the Elbow River had city officials warning homeowners about possible basement flooding.

Redwood Meadows, a townsite near Bragg Creek, has declared a state of emergency. The sewer system is overtaxed and officials are asking residents to reduce their use of the sewer system.

In the town of Okotoks, Sheep River Park was closed because of flooding; campers have been moved out of a local campground.

"There were about 30 RVs in the campground yesterday and they left to go to our Centennial Arena parking lot and camp out there for the night," said town spokeswoman Nancy Weigel.

Okotoks staff are filling sandbags and giving them to homes and businesses near the river.

Two provincial parks were closed because of the water. Red Lodge Provincial Park near Bowden and the group-use area at Wyndham-Carseland Provincial Park southeast of Calgary are shut until further notice, the province said.

In another development, the province has announced $25 million in disaster recovery funding for southern Alberta communities hit with flooding in April.