It’s been almost three months since Riley Zickel disappeared into the Oregon wilderness on what was supposed to be an overnight backpacking trip.

Sunday, more than two months after search efforts for the Analy High School graduate were suspended, a memorial service will be held at Bloomfield Farms, 4707 Bloomfield Road, in Petaluma.

The celebration will run from 4 to 9 p.m., said Riley’s mother, Erin Riley. There will be music, a fire and memories, she said. The family is asking attendees to bring potluck dishes.

“We’re coping,” she said. “The truth of it is he was only 21. But it’s kind of a beautiful story in the sense that he died doing something he loved so much more than anything in the world, and now he is literally part of the mountain.”

The 21-year-old was an experienced backpacker and a chemistry major at Lewis & Clark College in Portland. On July 27, he headed to the Mount Jefferson Wilderness in the Willamette National Forest, southeast of Portland.

It was meant to be an overnight trip, and he was set to meet a friend in Seattle afterward, but never arrived.

Searchers found his SUV parked at a trailhead.

Efforts to find him have been discontinued through winter, but will begin again this spring.

Donations to the Riley Zickel Search Fund on GoFundMe are meant to help alleviate some of the cost.

So far, $21,738 has been raised to pay for the search.

“It’s really sad,” Erin Riley said. “We miss him like crazy.”

You can reach Staff Writer Christi Warren at 707-521-5205 or christi.warren@pressdemocrat.com. On Twitter @SeaWarren.