Walden Grindle, 35, went to the top of the mountain by himself to "speed paraglide" Sunday, Capt. Tracey Stuart said.
"You stand there with your chute open and the wind pulls you up like a kite," Stuart said.
When Grindle crashed, his emergency response radio beacon sent a distress signal to the company that monitors the signals, Stuart said.
"They called us and gave us the coordinates," Stuart said.
Grindle also called his wife and told her that he thought he broke his hip. Grindle's wife then called the sheriff's office around 12:40 p.m. to see if they were on the way to the crash site, according to Stuart.
A California Highway Patrol helicopter flew to the mountainside and a medic on a long-line reached Grindle and pronounced him dead at the scene, Stuart said.
Grindle was taken by a fire truck to the main access dirt road at Robert Louis Stevenson State Park. An autopsy is scheduled for Tuesday.
Grindle worked since 2002 as the geographical information systems manager at Jack Neal & Son Vineyard Management in St. Helena and at Neal Family Vineyards winery in computer administration, web and graphic design, marketing materials and labeling, according to the company's website.
His duties included managing new technology applications in weather monitoring, vineyard imaging and field computer operations.
The company's president Mark Neal said he was too distraught to comment this morning.
Grindle and his wife Danielle got married in December.