Troopers say he apparently lost his footing and fell 80 to 100 feet to the base of the waterfall, located off a marked trail in an area described by police as "pretty treacherous".
Mendoza was flown to Albany Medical Center, where he was pronounced dead.
A family spokesperson says Mendoza was on a training hike with fellow students and faculty members when he died.
"He was a very wonderful guy, very incredibly brilliant, a brilliant chemist, very insightful. He was double majoring in chemistry and photography at Bard College," said Eric Campos, family spokesperson.
The death was the third on hiking trails in the area this year.
The Associated Press contributed to this report.
