RCMP said the driver died despite rescue efforts by witnesses and emergency personnel.
Cindy Rogers was driving by Wood Lake when she saw the accident and went into the freezing water to try to rescue the driver, whose name was not released.
Rogers said she felt she had no choice but to help.
“Someone’s life is down there, someone’s dead, someone’s life,” she said.
It wasn’t immediately known what caused the Jeep to go off the road or if other people were inside. The highway was closed for hours. — CP