04/07/2012 11:08 EDT | Updated 06/07/2012 05:12 EDT

Alberta Sisters Pulled From Icy Pond In Critical Condition

Flickr: dominiqs

Police and emergency officials in Alberta say they don't know how long two young girls were submerged in icy water before they were found on their family's rural property in central Alberta.

The girls, aged 5 and 3, were discovered unconscious in a slough, or small body of water, by family members who called RCMP around 10:20 a.m. MT Friday.

Emergency responders arrived from several locations to the property near Red Deer. The girls were first taken to hospital in Red Deer and then flown by STARS air ambulance to the Stollery Childrens' Hospital in Edmonton where they were listed in critical condition.

"We don't know how long they were left unsupervised or whether there was a parent or supervisor in the vicinity when this happened. We do know that emergency services managed to get there within 10 minutes of the 911 call. We just don't know how long they were in the water before that call was made," the CBC's John Northcott reported Saturday.

Emergency Medical Services spokesman Adam Loria said RCMP and fire crews delivered "a very quick response" when they were called to the property.

"From our angle we gave the best shot we could and hopefully everything works out," Loria said.

The girls were found submerged in 1.5-metre-deep water after slipping through the ice, RCMP said.

Their condition was so serious, STARS air ambulances from Calgary and Edmonton were called in, bringing three extra support staff each.

"Given the nature of the emergency today, a decision was made to pick up the specialty pediatric teams at the children's hospitals in Calgary and Edmonton," STARS spokesman Cam Heke told CBC News on Friday.

The aircraft landed minutes apart on the roof of Stollery Children's Hospital in Edmonton.

RCMP are investigating but said nothing indicates this was anything beyond a tragic accident.

Out of respect for the family's wishes, RCMP are not commenting on the medical condition of the two young girls.