It was the most serious of two kayaking accidents on the Green River within a few miles of one another.
The woman, believed to be in her 40s, had launched her kayak at Kanaskat-Palmer Recreation Area near Ravensdale. Her friends were able to pull her from the river after her kayak flipped and get her to shore.
Medics were called in while her companions administered CPR. She was taken to a local hospital in critical condition.
In the second incident on Sunday, a man flipped his kayak on Green River about two miles away from the first incident and was thrown into the water.
Deputies said he was inexperienced at kayaking, and that was likely the primary contributing cause of the accident.
The man was able to get himself out of the water. He was uninjured and was not taken to the hospital.