A woman was injured when she went over a waterfall Thursday in the Plotter Kill Preserve off Mariaville Road in Rotterdam.
She sustained head injuries and a helicopter was called to the scene, emergency radio traffic indicated.
The Plotterkill Volunteer Fire Company and Rotterdam Police Department were on the scene Thursday evening and into the night, with a command post set up at the Plotterkill firehouse.
There are three waterfalls in the preserve, which encompasses 632 acres of hardwood forest along the Plotter Kill, a tributary of the Mohawk River. The largest waterfall is 60 feet high; the other two are 40 feet high.
Emergency responders reached the woman before dusk but were still working to bring her out of the ravine after sunset.
The preserve has been the site of lengthy rescue missions before, given its steep slopes, ledges and rugged terrain. In 2011, a woman fell nearly 100 feet down a cliff she had been climbing. The rescue took about 21⁄2 hours and involved ropes and pulleys.
Many rescues at the preserve over the years have involved stranded hikers who get lost on the trails.