Three bodies have been discovered in a river near High River, Alta., during the province's worst flooding in decades, say the RCMP.

Floodwaters have caused massive disruptions in Calgary, as well as several other southern Alberta communities, including Canmore and High River.

"We did locate two people — one adult male and one adult female. Both have been recovered from the water," RCMP Sgt. Patricia Neely told CBC's Ian Hanomansing Friday evening.

"We have also located what is believed to be a third adult; however, due to the dangerous surroundings around this person, we have not yet been able to recover that person."

The identities of the victims have not been released.

As Albertans faced more rain Friday, the downpour has left hundreds of homes semi-submerged, lifted railroad tracks and inundated the Calgary Stampede grounds.

At least 100,000 Albertans, including about 75,000 Calgarians, have been forced out of their homes and large areas of Calgary's downtown core were being evacuated Friday afternoon.

• Map: See which Calgary neighbourhoods are affected
• See: Flood areas before and after
• Live updates: The latest from CBC reporters, Alberta officials
• See: Your photos of southern Alberta floods
• List: Alberta emergency contacts

Earlier Friday, four people were feared dead from the floods in High River, believed to be one of the areas hardest hit by the flooding.

Two men were seen floating apparently lifeless in Highwood River, but it's not clear that those were the bodies that have been recovered.

A woman and her camper were swept away in the Longview area of Highwood River. She has not been seen since.

A third man was seen falling from a canoe on the Highwood River, and it is unclear if he was able to get back into his canoe or make it to shore.

It is unclear if any of these are the bodies discovered in the late afternoon Friday by the RCMP, though police have said the woman remains unaccounted for. High River is about 60 kilometres south of Calgary.

'It's unbelievable'

Calgary Mayor Naheed Nenshi is urging Calgarians to stay away from the downtown core, where about 350,000 people typically work. Only a small fraction of them were at work Friday, as employees were asked to take a family day and offices were closed ahead of the expected flooding.

"No one could even imagine it," Calgary resident Russ Doherty said Friday. "It's unbelievable. We were here ... till nine or 10 last night ... but we had no expectation that it was going to get that high. Pretty amazing."

Sections of the main north-south link through Calgary, the Deerfoot Trail, were shut down Friday, adding to the city's transportation troubles.

Calgarians are being asked to limit water use. While the water is still safe to drink, people should refrain from using laundry machines and dishwashers.

Officials have asked people in downtown Calgary buildings without power to consider leaving, said emergency management director Bruce Burrell. Most buildings in the downtown core appear to be without power, said CBC's Terry Reith from Calgary.

A central Calgary emergency family shelter was forced to relocate its 85 residents, including 45 children. The Inn from the Cold shelter lost electricity during the flooding.

Of the displaced Albertans, almost all have found shelter with friends and relatives, officials said. The city has facilities for 2,500, but only 1,500 people are being sheltered currently, and there's no plan to expand the number of shelters.

• Strangers open homes to Calgary flood victims on Kijiji

Many people are arriving at the centres, receiving the information they need and then relocating to stay with family or friends.

Mass evacuations throughout Alberta

The flooding has resulted in mass evacuations throughout Calgary and southern areas of the province.

Banff issued evacuation orders for the Rocky Mountain Housing Co-operative Phase 2 after deeming it unsafe. Organizers of the inaugural Banff Marathon, scheduled for Sunday, cancelled the event.

Lethbridge and Medicine Hat declared a state of emergency Friday afternoon.

In Medicine Hat, residents in low-lying areas were told to leave their homes along the river. The mandatory evacuation is expected to include about 3,800 homes and 10,000 residents.

Edmonton and the town of Devon declared a flood watch, which is the lowest level of flood-related warning, early Friday evening. Water levels in the North Saskatchewan River could rise by 3½ metres.

First responders' efforts praised

"We're going to get through it, but we're not through it yet," said Alberta Premier Alison Redford to CBC's Ian Hanomansing.

She said the primary concern is making sure people are safe and then rebuilding after the flood's damage.

Earlier, the premier said she had spoken with Prime Minister Stephen Harper, who "offered to work closely with us and provide any possible support," she said.

Harper arrived in Calgary to tour the flooded areas with Redford at 3 p.m. ET.

• Harper joins Redford for 'first-hand look' at flooding

Nenshi seemed clearly relieved at the help the city has been getting from the provincial and federal governments, which included air support from the Forces to rescue 31 people stranded on rooftops overnight.

The Forces sent as many as 1,300 soldiers to southern Alberta for help with search and rescue, humanitarian aid, and moving people back into their homes.

Edmonton police sent 100 officers to help with transportation and security issues during the evacuations.

High River looks 'like a lake'

In High River, officials were "about to start the door-to-door operation," Wildrose Party Leader Danielle Smith said Friday afternoon.

"We've got a number of search and rescue helicopters in town," she told CBC's Rosemary Barton.

Search officials were going to go door-to-door to make sure they had identified people in need of assistance, Smith said, noting that there are a lot of senior citizens in High River.

The next step would be recovery, Smith said. The lengthy list of tasks include making sure the water and sewage systems are working, along with gas and electricity.

"And then they'll start the hard process of getting people back into the town, but it's going to take a number of days before we can get to that point," she said.

Smith said on Thursday, it was "like a lake" in High River. "It was unbelievable to see how much water had spread over the town."

She said about three-quarters of the town had been "massively impacted" by water damage, saying some homes would need to be condemned.

"When you have this amount of damage, we're not talking in terms of weeks or months," Smith said. "This is probably going to take two to three years before everybody is able to get back in their homes and also have all of the repairs done so we can get everything back to normal."

Recovery efforts already planned

Municipal Affairs Minister Doug Griffiths echoed Redford's assurances to Albertans that emergency management efforts are underway.

View a map of the evacuated areas

"I want you to know that we are keenly aware that now we are managing a crisis situation," Griffiths said. "But we are also planning for the future already."

When the water subsides and it’s time to clean up the debris and rebuild, he said, Albertans will be doing that as quickly as possible.

The city's Scotiabank Saddledome and the Stampede grounds were flooded as of mid-afternoon. However, the mayor said the grounds would be ready for Calgary's annual Stampede, which is scheduled to run July 5-14.

"You know what? We’re Calgarians," said Nenshi. "We'll make it work."

The swollen Bow and Elbow rivers carried water fast and furious overnight through Calgary and towns such as Canmore, High River, Black Diamond and Turner Valley.

Both rivers were believed to have crested in the Calgary area by about 6 a.m. MT.

While not as intense as Thursday, more rain was forecast for Friday, with an additional 15-30 mm possible, said CBC meteorologist Jay Scotland.

"The greatest amounts were expected west of Calgary and just north of Canmore, and an additional five to 10 mm tonight through Saturday morning," he said. "Showers also remain in the forecast this weekend."

By Saturday, the heaviest rainfall should be over, said CBC's meteorologist Ross Hull.

But neighbouring provinces Saskatchewan and B.C. are bracing for spillover from the floods.

"I urge all British Columbians who live in areas vulnerable to flooding to be prepared and have a plan," said B.C. Premier Christy Clark in a statement.

• Evacuations ordered in Elk Valley, mudslides hit near Kaslo
• Saskatchewan River expected to flood

The Mission Creek flow rate has dropped, but evacuation alerts in the Southeast are in place.

Meanwhile, the Water Security Agency is warning Saskatchewan residents of upcoming flooding along the South Saskatchewan River, which is predicted to peak on Monday.

The evacuation process for Cumberland House, Sask., where the North and South Saskatchewan Rivers meet has already begun.

You can find information from the City of Calgary here.

With files from The Canadian Press