Vernal Falls

A May 2009 photo of Vernal Falls in Yosemite National Park. The Vernal Fall footbridge offers one of the first vantage points of the waterfall along the park's popular Mist Trail. (Mark Boster / Los Angeles Times / August 16, 2012)

YOSEMITE VALLEY, Calif. -- A 10-year-old boy drowned and a 6-year-old boy was missing after the two were swept down the Merced River in Yosemite National Park during a family outing Wednesday afternoon, park officials said.

Search-and-rescue efforts were ongoing Thursday morning for the 6-year-old as crews combed the banks downriver from the Vernal Fall footbridge, a popular stop beneath the waterfall along the park's most-used Mist Trail, said park spokesman Scott Gediman.

The extended family, who were visiting the park from Southern California, began their hike at the Happy Isles Trailhead and stopped near the footbridge about 3 p.m. to cool off in the river, Gediman said. At some point, the boys were caught in the current and swept downstream.

The 10-year-old was pulled out about 150 yards downriver and, despite resuscitation efforts by another park visitor and rangers, was pronounced dead, Gediman said.

A search for the second boy began immediately, Gediman said. Crews have focused their efforts on an area between the footbridge and Happy Isles, a stretch of river laced with boulders more prominent this season because of low water levels.

Still, Gediman said, the Merced's current remains surprisingly strong.

The 10-year-old's death marks the third drowning at the park this year, Gediman said. Last year, three people died after being swept over Vernal Fall itself.