OLYMPIA, Wash. -

The Thurston County sheriff's office says a woman drowned over the weekend while inner-tubing with her teenage grandson on the Nisqually River.

The News Tribune reports that the 58-year-old woman died early Sunday at Providence St. Peter Hospital in Olympia, where she was taken after bystanders performed CPR.

Witnesses heard commotion and found the woman hanging onto a snag near the Riverbend Campground with her 14-year-old grandson. The sheriff's office says neither was wearing a life vest.

The boy made it to shore, but his grandmother lost her grip and was caught on the root-ball of a fallen tree. Even though the water was shallow, deputies say the fast current kept witnesses from reaching her on foot.

Others got to her with a boat, pulled her in and started CPR.

Officials have not released her name.