UPDATE 1PM:
The woman has been flown to the John Hunter in a stable condition, suffering head and pelvic injuries.
EARLIER:
The Hunter's Westpac Rescue Helicopter crew has winched a doctor and paramedic into Glenrock Reserve to treat a young woman injured in a fall.
The 18-year-old is believed to have fallen around 3 metres down a waterfall near a viewing platform.
She's expected to be winched out and airlifted to the John Hunter Hospital, while the extent of her injuries is not yet known.
