04/07/2012 03:05 EDT | Updated 06/07/2012 05:12 EDT

Police and EMS don't know how long sisters were submerged after fall through ice

RED DEER, - 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.

Police say the children, aged 3 and 5, and fell through the ice on Friday morning on a rural property near Red Deer.

Family members found the two sisters and called emergency services.

EMS spokesman Adam Loria says the girls were unconscious and were rushed to hospital in Red Deer in critical condition, and were then transported by helicopter to Edmonton.

An update on the condition of the girls isn't available.

Police say ice conditions in the province are poor due to warm weather.