More than 100,000 people have ascended skyward in Irvine's balloon ride to get expansive views of Orange County, take panoramic photographs and even make the occasional marriage proposal.

But imagine the shock the pilot of the Great Park balloon must have felt just before 9 p.m. Sunday when, while high above the ground, the gondola shook and a young man parachuted out.

The orange-hued helium balloon had ascended to a height of 330 feet when one of the 12 passengers climbed up and out of the netting enclosing the gondola, unfurled a hidden parachute, threw it in front of him and jumped out, said Irvine city spokesman Craig Reem.

After landing on the tarmac about 100 feet away from the tethered craft, the unidentified man picked up his parachute and ran off, jumping over a fence to where a driver in a white Toyota Supra waited with the engine running. The two sped off before authorities could catch them.

"The idea of any balloon is to take people up and take them down safely, not to have them jump out at any height," Reem said. "What this guy did was pretty dangerous."

Irvine officials said they would like to find the jumper and are looking into whether the leap violated federal aviation rules against base jumping in populated areas, but they did not involve police because of the quickness of the getaway, Reem said.

Reem described the jumper as a man in his mid-20s, 5-feet-11 and 180 pounds, with blond hair. He was wearing a black jacket and blue jeans.

"He knew how to use a parachute," Reem said.

It wasn't the only incident to take place over the weekend at an attraction at the Great Park, which is being converted from a military airfield into a sprawling, 1,350-acre public park. Earlier Sunday, a 48-year-old woman was hospitalized after she slipped and hit her head in an old hangar being used for ice skating.

The balloon ride had been operating since July 2007 without any recorded accidents or incidents, Reem said.

"Our sincere hope is that no one tries this again," he said.

-- Tony Barboza in Orange County