Emergency officials in Medicine Hat, Alta., are reinforcing city infrastructure and forcing a handful of resistant residents out of the mandatory evacuation zone as rising water levels — that have devastated several southern Alberta communities, including large parts of Calgary — reach the South Saskatchewan River.

Rising waters have forced the closure of most of the city's key transit arteries. Medicine Hat officials closed access to two of the three city's bridges at 10 a.m. MT — Maple Avenue Bridge and Findlay Bridge. The last, the Trans-Canada Highway bridge, was slated to be closed at 7 p.m. MT but Alberta Transportation announced that the bridge will remain open. However, officials stress that floating debris in the river water is still a concern.

Trans-Canada Highway bridge stays open

The city has begun emergency preparedness by setting up shelters and temporary facilities in both the north and the south sections of the city.

Alberta Health Services will set up a field hospital in the Medicine Hat Leisure Centre, which will stay open 24 hours a day to provide emergency care and maternity services to the residents in the north of the city.

The city opened two emergency care shelters to house people displaced by the floods.

"I'm banking on a lot worse than what people are expecting," one Medicine Hat resident told CBC News, adding that some people have been reluctant to leave because they did not face danger in the city's last round of flooding.

Preparing for this scenario, emergency crews have already been dispatched to both sides of the city.

"This is going to be a very challenging time for Medicine Hat," Alberta Premier Alison Redford said on a visit to the city on Saturday evening. "There's going to be a lot of uncertainty and people are going to be afraid. I want people to know we have the opportunity to get through this."

Schools closed

The city also announced the closure of the majority of schools throughout the city. Also, the city has directed all municipal employees to remain at home on Monday and Tuesday.

The river is flowing at 5,000 cubic metres per second, and is expected to peak Monday morning at 1 a.m. MT with flows reaching 5,300 cubic metres per second, which, according to experts, is the equivalent of the contents of two Olympic-sized swimming pools passing by per second.

Earlier, officials believed the river would peak at 7 a.m. MT.

Initially, emergency crews expected two rivers to merge and all the water to rush down through South Saskatchewan River. Those high waters didn't arrive at the same time which provided a little relief for emergency crewssome relief for officials

"We're feeling optimistic now… We were a little anxious this morning." said the city's deputy fire chief Doug Cooke.

Overland flooding in the city's affected areas has risen to just under a metre.

"It's pretty high now and it's climbing even higher than this," said Norm Boucher, the city's mayor.

Initially experts felt that Monday's flows would be the highest ever recorded in the 60,000-person community. In 1995, water flows peaked at 5,200 cubic metres per second.

In 2005 flooding from the river caused $383 million in damages to homes and city infrastructure.

By mid-morning, curious residents came out to Findlay Bridge to watch the rising river, which carried large branches and wooden planks in its current.

Crystal Bollinger has lived in Medicine Hat her entire life and went to the bridge with her family.

"I have never seen it like this, not even in 1995," said Bollinger, adding that she believes many people will be up Sunday night watching the river — just not from the bridge.

City officials are asking residents to stay away from all waterways, bridges, banks and evacuation zones.

"Rescue from the river may not be possible at this time," said Ron Robinson, the director of emergency services.

Robsinson, who took an aerial survey of the river, said most of the 3,800 homes would likely have sustained flood damage from either overflowing sewage or overland flooding.

"It looks like the muddy waters of the Mississippi," said Robinson.

Already, workers have installed two pumps at City Hall to remove some seepage and are reinforcing the walls with sandbags, and emergency officials continue to work to secure the city's power and water plants. Floodwaters have started pouring into Lions Park.

Mandatory evacuations

Some 10,000 people have been ordered to leave their homes along the South Saskatchewan's banks. Officials have turned off gas and power to the homes in the evacuation area.

But, 10 people were refusing to heed the mandatory evacuation, said Robinson. Police are at their homes, attempting to convince them to leave.

Under the Emergency Management Act, police have the authority to fine or arrest anyone who refuses to follow a mandatory evacuation, he said.

"We need to protect lives, even if they don't want us to."

Brad Pletz lives in the mandatory evacuation zone, but did not heed the warnings until this morning. Pletz woke up and the power in his house had been turned off.

"I can pretty much take a boat out of my house right now," he said, adding the police came to his place and told him he had to go.

Across Alberta, some 175,000 people were ordered to leave their homes as the floods ravaged the province's southern communities. At least three people died in High River, which is about 60 kilometres south of Calgary and is believed to be one of the hardest-hit communities in the province.

In Calgary, the floodwaters filled the city's iconic Saddledome stadium up to the 10th row of seats and washed out the Calgary stampede grounds. The city's annual stampede is scheduled to run July 5-14.

Surrounding areas flooded

South of Calgary and west of Medicine Hat, the city of Lethbridge and Lethbridge county also feared the floodwaters would pass through. However, both areas ended their states of local emergency on Saturday.

Lethbridge has about 84,000 residents, while the county has slightly more than 10,000.

In Drumheller, north east of Calgary, about 4,000 residents were being asked to leave their homes. The Red Deer River, which runs through the town, was expected to peak overnight Sunday.

At Siksika First Nation, east of Calgary, about 1,000 people had to relocate, and the territory is under a boil water advisory.

"You're going to be completely shocked when you get out there," receptionist Louella told CBC News. She said some houses in the community have been completely washed away.