Arrest warrants have been issued after two inmates "walked away" and escaped from a minimum-security unit in Stony Mountain Institution in Manitoba.

William Benjamin Hunter-Garrioch, 21, and Dale Jacob Gilchrist, 34, escaped from the federal penitentiary Saturday night, Correctional Service Canada (CSC) said in a release.

Guards noticed they were missing during a head count at about 10 p.m., said Stony Mountain assistant warden Guy Langlois.

He said the pair escaped from the facility, which is located about 25 kilometres north of Winnipeg, during regularly scheduled outdoor exercise.

There is no perimeter fencing surrounding the minimum security outdoor area, Langlois said.

"The prison routine allows for movement on the grounds, so they could've been picked up or walked away," he said, adding it is considered an escape when minimum security inmates leave without permission.

"Every escape we have is taken very seriously."

'Serious convictions'

Hunter-Garrioch was serving nine years for attempted murder, among other offences. In 2014, Winnipeg police arrested him after he allegedly shot a 24-year-old woman at a rooming house. The woman was taken to hospital and eventually upgraded from unstable to stable condition.

He is 5-foot-7, weighs about 125 pounds and has brown eyes and brown hair. He also has a scar on his left wrist.

Gilchrist, who is from Saskatoon, was serving a six-year sentence for armed robbery. He was arrested in 2015 after he and another man robbed a pharmacy in Brandon, Man., police told CBC News. He also previously served sentences for assault, theft and carrying a concealed weapon, CSC said.

He is 6-foot-2, weighs about 200 pounds and has blue eyes and brown hair. He also has tattoos on his midsection, chest, arms, neck, hands and right leg, according to CSC.

Stony Mountain Institution is a federal facility located about 25 kilometres north of Winnipeg. (Justin Fraser/CBC)

"They've got some pretty serious convictions under their belt, so that's why we're asking the public not to be in contact with them," said RCMP Sgt. Paul Manaigre.

Police believe the men were picked up and headed to Winnipeg or Saskatchewan, although there's a chance they also stole a vehicle, he said.

"We don't have any information to suggest that anyone is in any danger or anything, but when two people have been convicted of serious offences they need to complete those sentences and we're asking them to help us put them back in jail."

Transitional unit

Stony Mountain prison's minimum-security unit is transitional in nature and meant to help men more easily reintegrate into society upon release, according to Langlois.

"The environment of a minimum-security institution is intended to develop an inmate's capacity to function back into society with minimal monitoring, so it's making the way to their eventual release," he said.

"It plays an important role in reintegrating offenders back into the community and helping them become law-abiding citizens."

We're concerned and we'll look at all the factors as the review takes place. - Guy Langlois , assistant warden, Stony Mountain Institution

There are 27 housing units in minimum security. Inmates can move freely between them, administration buildings and a visiting area, he said.

The area is monitored by guards. Inmates are required to be back in their living area during mandatory head counts. Langlois said the number of guard staff on shift during the escape was at regular levels as far as he knows.

Men assigned to live in the minimum security unit must first pass a thorough screening assessment.

"Only those offenders who are assessed as having a low-risk to public safety are placed in that environment," said Langlois, adding the same would be true for Hunter-Garrioch and Gilchrist.

Rare escape

One man serving time in Stony Mountain escaped in 2015 during an escorted medical appointment, but Langlois says there haven't been any escape attempts from the minimum security unit lately. He said it's "unlikely" Hunter-Garrioch and Gilchrist will be placed there again if they are arrested.

Langlois said such escapes are rare at Stony Mountain, though he said it does occasionally happen in other minimum-security units in Canada.

Convicted murderer Steven Bugden was serving a life-sentence in a New Brunswick prison when he, too, walked away from the facility earlier this month. RCMP eventually tracked him down by following footprints in the snow that led away from the prison.

Danielle Manaigre (who is of no relation to Sgt. Paul Manaigre) said this is the first time someone has escaped since she moved to the community of Stony Mountain two years ago.

Danielle Manaigre said she generally feels safe living near Stony Mountain Institution but wondered why people who live nearby weren't notified directly of the prisoners' escape. (Justin Fraser/CBC)

She, her fiancé and her neighbour didn't find out about the Saturday night escape until Sunday afternoon.

"It's always in the back of our mind living here," she said. "But it is kind of concerning that nothing [from Stony Mountain Institution] is being advised to the people that live here."

Correctional Service Canada plans to investigate how the Stony Mountain escape happened and has informed local police service.

"Of course we're concerned and we'll look at all the factors as the review takes place ... and determine if there's bigger issues," Langlois said.

RCMP are searching and anyone with information of their whereabouts is asked to avoid the men and call police.