CALGARY, Alberta – Flooding forced the western Canadian city of Calgary to order the evacuation of its entire downtown Friday, as the waters reached the 10th row of the city’s hockey arena.

Communities throughout southern Alberta were inundated by overflowing rivers that washed out roads and bridges, soaked homes and turned streets into dirt-brown waterways. Police said as many as four people might have died.

About 350,000 people work in downtown Calgary on a typical day. However, officials said few people need to be moved out, because many heeded warnings and did not go to work Friday.

Twenty-five neighborhoods in the city, with an estimated population of 75,000, have already been evacuated due to floodwaters in Calgary, a city of more than 1 million people that hosted the 1988 Winter Olympics and serves as the center of Canada’s oil industry.

Outside the city, the Royal Canadian Mounted Police said two men were seen floating lifeless in the Highwood River near the community of High River on Thursday, but no bodies have been found. They said a woman who was swept away with her camper has not been located. And it wasn’t clear whether a man who was seen falling out of a canoe in the High River area was able to climb back in.

In downtown Calgary, water was inundating homes and businesses in the shadow of skyscrapers. Water has swamped cars and train tracks.

The city said the home rink of the National Hockey League’s Calgary Flames flooded and the water inside was 10 rows deep.

At the grounds for the world-famous Calgary Stampede fair, scheduled for July 5-14, water reached up to the roofs of the chuck wagon barns. The popular rodeo and festival is the city’s signature event. Mayor Naheed Nenshi said it will occur no matter what.

About 1,500 people have gone to emergency shelters while the rest have found shelter with family or friends, Nenshi said.

Nenshi said he’s never seen the rivers reach so high or flow so fast, but he said the flooding situation was as under control as it could be. Nenshi said the Elbow River, one of two rivers that flow through the southern Alberta city, has peaked.

The mayor suggested that levels on the Bow River would remain steady for the rest of the day as long as conditions didn’t change.