Search Fails to Turn Up 2 Missing Boys : Accident: The pair were swept away in a frigid river and are presumed drowned. The children and an aunt who died were part of a Compton family’s outing in Yosemite.

A team of more than 15 rescuers combed the banks of the cold, turbulent Merced River for a second day Sunday, searching for the bodies of two young boys who were presumed drowned after their aunt fell asleep at the wheel of her car, plunging the vehicle into the water.

As the rescue effort continued without success, new details of the Saturday morning accident in Yosemite emerged, including the identities of the family members, all of whom are said to be from Compton.

Authorities said 3-year-old Mario Thomas and his 5-year-old brother, Lance Thomas Jr., jumped into the roiling, 40-degree waters of the Merced as passersby attempted to rescue the family. The boys apparently thought they were to follow their 7-year-old sister, Sequoia, who had a rope tied around her waist and was being pulled to safety.

The children’s aunt, 44-year-old Elaine Watson, then jumped in after the boys, but drowned while trying to save them.

The accident, which occurred just after dawn Saturday, turned what was to be a family gathering at Yosemite National Park into a tragedy. Sequoia Thomas survived, as did the children’s grandmother, 62-year-old Pearl Watson Jordon.

By Sunday afternoon, authorities said there was not much hope that Lance and Mario would be found alive.

“It’s a tough situation,” said park spokeswoman Kris Fister. “The river is at its peak now in terms of the flow of the water, and the depth and the temperature being quite cold right now. It’s a dangerous time. . . . Obviously, it doesn’t look good.”

Fister said a team of between 15 and 20 rescuers from the National Park Service had been combing the swollen river’s banks. She said a search dog trained to pick up human scents was involved in the effort and that park rangers in wet suits have been snorkeling in the river’s calm pools, hoping to find the boys.

In addition, a helicopter had joined in the search, and two lookouts were posted along the river--one at a bridge and the other at a dam downstream from where the accident occurred. The search was halted at 4:30 p.m. Sunday and will resume today, Fister said.

According to Fister, the Thomas children and their aunt and grandmother were visiting the park for a family gathering. Although the children’s parents were not at Yosemite then, other relatives were in the park, she said.

Fister said investigators did not find any skid marks at the scene. They were told by Jordon that Watson fell asleep at the wheel just as the park highway curves slightly.

“At that point the river is quite close to the edge of the road,” Fister said, “and so she simply just went in.”

The family escaped through the rear windshield and waited on the trunk until the passersby arrived. The passersby, who have not been named, threw a rope to the group, which Watson tied around the waist of Sequoia.

After the girl jumped in the water, her brothers and aunt followed. Watson’s body was found about half a mile down the river. The grandmother was rescued by park rangers.