A Southern California man taking part in what is considered one of America's most grueling bicycle rides has been killed after he lost control of his bicycle and hit a tree.

Nicola Grossi, of La Mesa, Calif., was riding downhill on a road near Shaver Lake, in the Sierra Nevada about 60 miles northeast of Fresno, when he lost control of his bicycle on a curve, went off an embankment and hit the tree around 10:30 a.m. Saturday, authorities said.

CHP officers, deputies and paramedics tried to render medical aid, but Grossi died at the scene, the CHP said.

Grossi was taking part in the Climb to Kaiser, an endurance ride considered to be one America's 10 toughest bike rides, as rated by Bicycling Magazine. He was listed as a first-time participant.

"You never want something like this to happen," ride organizer John Craft told the Fresno Bee.

"When you're going at high speeds on windy roads, sometimes unfortunate things like this can happen though."

Craft said the section of roadway leading to where Grossi crashed is marked with cautionary signs.

In addition, the event's handout material that maps out directions and rest stops states for that area: "Steep and winding; use caution on descents."

The event's website says the ride, which begins in Clovis, is 155 miles long and requires 13,500 feet of climbing, though shorter 62- and 100-mile rides are offered.

Grossi, listed on the event's registration list as 42-years-old, was one of 373 bicyclists registered for the ride.

The Fresno County Coroner's Office said an autopsy was scheduled.