Five people are dead, including two Canadian Forces members, in two separate single-vehicle accidents Sunday morning amid dangerous road conditions due to weather in Manitoba.

In one crash, two soldiers were killed, and a third is in serious condition near Brandon, Man., the RCMP said Sunday.

The four male passengers in the vehicle were members of the Canadian Forces and are stationed at CFB Shilo.

The accident, a single-vehicle rollover, occurred at about 12:30 a.m. early Sunday morning when the SUV the men were travelling in went off a bridge on Provincial Road 457 about six kilometres east of Brandon, Man.

A second accident occurred near Hamiota, northwest of Brandon, claiming three lives when a pickup truck carrying five people slammed into a tree early Sunday.

Police said the 23-year-old male driver and a 35-year old woman, both from Hamiota, Man., and a 35-year-old man from the Rural Municipality of Woodworth were killed.

A man and woman were also treated for injuries.

Police said road conditions were dangerous at the time.

In the accident involving the Canadian Forces members, police said the men were riding in a 2003 Ford Escape when it lost control on the bridge over Willow Creek, hit the guard rail and left the bridge, landing on its roof partially submerged in the creek below.

One of the passengers who was seated in the rear of the vehicle was able to climb out, make his way back up to the roadway and get help from other motorists.

According to the RCMP a heavy snowfall on Saturday had created slippery and snow-packed road conditions.

The 26-year-old driver of the vehicle and a 24-year-old passenger in the front seat died at the scene.

A 27-year-old passenger who was seated in the rear of the vehicle is in serious condition with life-threatening injuries.

The fourth male passenger, who was able to escape the vehicle and get help, sustained non-life threatening injuries in the accident.

The survivors are being treated at the Brandon Regional Health Centre.

None of the passengers' names are being released, pending notification of next of kin.

Flooding fears

The snowstorm is expected to worsen high river levels across much of the Prairies.

Manitoba Premier Greg Selinger said water levels will stay high for longer because of the weekend precipitation, pushing the province's flood defences.

"It's a stark reminder of how quickly things can change," he said at a press conference Saturday.

The government warned high winds could push ice onto the shores of many lakes, leading to the possibility that some dikes could be overwhelmed.