The 72-year-old succumbed to "severe hypothermia" after capsizing on Lake Carrera and slipping into its near-freezing waters, Carlos Salazar, the emergency room doctor, told Biobio Radio.
Tompkins was kayaking with four other Americans and a Mexican on the lake when violent winds sprang up in the afternoon, generating waves that tossed them all into the water.
A Chilean navy ship rescued the group and Tompkins was taken by private helicopter to the hospital in the town of Coyhaique where, despite doctors' efforts, he died.
Four years later he helped his first wife, Susie Tompkins Buell, establish the clothing brand Esprit and grow it into a big business before their divorce in 1989.
After selling his stakes in The North Face and Esprit for a fortune, Tompkins retired to Chile in 1990 and became a noted conservationist and philanthropist.
He worked to create a string of natural parks, and donated 8,000 square kilometers (3,000 square miles) to Chile and Argentina to help preserve a forest region on their border.
"Lately I've been paying more attention to my biological clock. I tell myself to hurry up, that I have to do everything before death catches me," he told the magazine.
