A call was received by Yellowknife RCMP around 9:30 p.m. about four adults and one 11-year-old child who became stranded about 1.5 kilometres north of the Yellowknife River bridge.
None were injured as a result of the incident.
Sgt. Bruce MacGregor of the Yellowknife RCMP said he assisted in co-ordinating the Yellowknife Search and Rescue team.
"(The snowmobilers) had a fire going, so they weren't in any immediate danger but they were stuck so we had to go in and get them out," he said.
Darcy Hernblad, deputy fire chief of operations at the Yellowknife Fire Department, said they received the call to assist at 12:50 a.m. Sunday.
"We responded with our rescue truck and trailer with two snowmobiles and rescue sled."
"We were giving assistance to Yellowknife Search and Rescue. They were already in there trying to get those people out but they got all hung up in the overflow themselves," Hernblad said.
"Not only did we have the original people stuck but we had the SAR people who needed help as well."
One snowmobiler and two SAR members had mild hypothermia. Hernblad said this is an exceptional winter because of snowfall, resulting in overflow on lakes and rivers. Water sits atop the ice, underneath the snowfall, he explained. "The minute somebody goes along in their snow machine, it sucks them right down until they get stuck."
Hernblad said there is no way to predict overflow.
If a snowmobiler keeps up their speed through small parts of overflow, they usually can get through it, but over long distances, the machine will bog down, he said.