RCMP say the first crash involved a Toyota, a Ford and a commercial truck in snowy conditions on the Coquihalla Highway on Sunday night.
The West Kelowna woman, along with two men, got out of their vehicles to help the injured in another car.
Police say a fourth vehicle then plowed through the accident scene, and while the men were able to jump out of the way, the woman was struck and later died in hospital.
Police say the woman got married just four months ago and her husband witnessed the crash.
RCMP also say the driver of the fourth car left the scene and drove to the RCMP detachment in Hope, he has been co-operating with investigators and speed and alcohol don't appear to be factors in the fatal crash.