Prime Minister Stephen Harper, who travelled to Alberta to witness the damage done by floodwaters in southern Alberta and Calgary, says the magnitude of the flood in the province's most populous city is "just extraordinary."

Harper met Alberta Premier Alison Redford and Calgary Mayor Naheed Nenshi at the Calgary airport just after 3 p.m. MT where he received a briefing before taking a helicopter tour of the flood-damaged areas.

Harper and Redford had spoken by phone earlier Friday and agreed to a co-ordinated response to the disaster. Harper also spoke to Nenshi, who provided an update on the situation in his city, which includes Harper's riding of Calgary Southwest.

The prime minister said at a Friday evening news conference that there are concerns that if the flood worsens, it could have "real impact on infrastructure and other services longer term" in Calgary, but he encouraged people to be optimistic and patient as the situation evolves.

He praised the work of his colleagues in the province and the city, as well as emergency workers and the general public.

"This is a very resilient place, and when the worst passes I know everybody will rebuild and get back to life."

Harper said the federal government provides emergency services and equipment, pointing to support from the Armed Forces as an example.

"Beyond that, there is the federal disaster assistance financial arrangement," he said. "It's legislation, there's a set formula and the distribution of monies will be all based on that after all of this passes."

Redford praised southern Albertans, saying things have gone very well in very tragic circumstances, but she cautioned  that some communities, including Medicine Hat, are still waiting for rivers to peak.

In an interview airing Saturday on CBC Radio's The House, Calgary Mayor Naheed Nenshi applauded the trilateral co-operation to the flood response but warned "the property damage will be immense."

"We won't know that for weeks or months until we really examine the state of roads and bridges… but I can tell you it is big," Nenshi said.

Asked if the Conservative Party policy convention scheduled to get underway next Thursday in Calgary should go ahead as planned, Nenshi said the number one priority is to make sure everyone is safe.

"If they are, we will welcome them with open arms. And if they're not, 'à bientôt' we'll do it the next time," the Calgary mayor said.

Conservative Party officials say they will monitor the situation over the weekend and provide delegates to the convention with an update on Monday.

Floods claim first victims

Officials confirmed on Friday evening that three people have died, but because of the dangerous flooding teams have yet to recover one of the bodies.

In an interview on CBC News Network's Power & Politics earlier Friday, Immigration Minister Jason Kenney said the scene on the ground was "surreal."

"It's unbelievable," Kenney told CBC's Rosemary Barton. "I've lived in Calgary for nearly two decades.… It's surreal."

Kenney, the federal minister responsible for southern Alberta, said the Bow River looks like a different river.

"It's a ferocious body of water right now."

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Vehicles surrounded by floodwaters are seen in the neighbourhood of Sunnyside in Calgary. Harper called the flooding in the city incredible. (Todd Korol/Reuters)

The Calgary MP said the federal government is focused on the emergency response.

"Given the rain, and the fact that the floods are moving downriver towards areas in the Prairies, this is far from over," he said. "We'll have plenty of time to deal with issues about funding, cleanup."

Kenney said the response in Calgary has been amazing, noting that some evacuation centres have more volunteers than they can use.

"In a situation like this, that's a good problem to have."

Canadian Forces from Edmonton have been mobilized to aid in rescue efforts, including 600 soldiers en route to southern Alberta. Another 600 troops were expected to be deployed by mid-afternoon, and will be directed by the province.

The Armed Forces already have reconnaissance parties in Cochrane, High River and Calgary, assessing what is going on.

There are three priorities for the troops: search and rescue, humanitarian aid and moving people back into their homes.

Officials say as many as 100,000 people in southern Alberta may have left their homes because of concerns about water levels.

Earlier Friday, Wildrose Party Leader Danielle Smith described the scene in High River, a town of roughly 12,000 people located south of Calgary.

Smith said that 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.

Federal NDP Leader Tom Mulcair praised Nenshi for his leadership through the flooding and offered a tribute to other officials and emergency workers.

"I would like to acknowledge municipal, provincial and federal officials, in particular first responders, and salute their hard work and professionalism under difficult circumstances," Mulcair said in a statement.

"Our thoughts and prayers are with all those facing flooded homes and evacuations."

With files from The Canadian Press