A large rock, weighing an estimated 50 pounds, fell shortly after noon today onto a 39-year-old woman hiking the Makuku Stream Trail in Nuuanu, seriously injuring her.

The Honolulu Fire Department received the 911 call at 12:08 p.m. and the first of five units with 16 personnel got to the scene at 12:18 p.m.

Air 1 transported rescue personnel to the location of the injured hiker, who was not pinned.

They assessed her condition, treated and secured her in a Stokes Basket and transported her to a landing zone at the nearby Nuuanu Reservoir.

HFD transferred her care to Emergency Medical Services personnel at 1:44 p.m.

She sustained injuries to her lower extremities, EMS said. She was taken by ambulance in serious but stable condition to Tripler Army Medical Center.

The woman had been hiking in a group of 14 adults for about three and a half hours when the rock fell on her.

No one else was injured and made it out on their own.