Friends and relatives of a young Petaluma woman who died in the snow after attending an outdoor New Year's Eve concert in South Lake Tahoe are trying to use their grief to help others avert tragedy.

Using funds donated in memory of their daughter, Alyssa, 19, Kim and Kevin Byrne and others have launched a public service campaign promoting a buddy system to help keep teens and young people out of danger.

They're targeting middle- and high-school children, asking them to pledge to seek safety in numbers, and encouraging them to call a trusted adult at the first sign of trouble.

Assigning buddies is a tradition for outings involving young children, who customarily double up and hold hands so all can be accounted for in a group.

But even older children need to stick together, and beyond that know to get help and whom to call if a buddy is at risk, Kevin Byrne said.

A key piece of advice offered through the campaign, dubbed "Always Buddy," is that kids whose cellphones are packed with friends' phone numbers should make sure they also have contact numbers for their friends' parents or other family members.

"It's your responsibility to reach out, talk to your buddy, have a contact list of who to go to if you think something is going wrong," Kevin Byrne said.

Kevin Byrne said he knows that kids never want to tell on a friend or get their friend in trouble, but kids need to get over that and realize that to keep their friends safe, sometimes adults need to be brought into a situation.

"Always Buddy" is born of lessons learned from Alyssa Byrne's death and a desire for something positive to come out of it. But it's also steeped in the love the Byrnes have both received and cultivated in its wake.

"Kevin and I and Greg (their son) count ourselves so fortunate to live in this town that has been nothing but loving and supportive," Kim Miller-Byrne said. "We definitely want to pay it forward in any way we can."

The Byrnes' daughter, a 2011 Casa Grande High School graduate, disappeared New Year's Eve and died alone -- her body frozen in the snow for three days before a utility worker peered over a snowbank and discovered it.

Byrne had gone to Tahoe with three friends, shared a room with them at a hotel in Stateline, Nev., and attended the three-day SnowGlobe Music Festival in their company, as well as hanging out with many other friends from Petaluma who drove up for the event.

But the last night of the concert, Byrne was walking ahead of her friends when she apparently decided to go back to the hotel before the last show was over. She left without a word, though she later told one of them by phone that she was on a shuttle bus heading back to Stateline. Authorities now believe Byrne decided to walk to the hotel, frustrated like many other concertgoers by the long wait for a bus.

They presume from the location of her body that she turned the wrong way on a main road back to Stateline. The temperature dropped below freezing that night, and friends said she had been drinking.

Kevin Byrne has been leading the buddy campaign in conjunction with several younger friends, including one who decided at Alyssa's memorial service that those in attendance should take a pledge to stay together when they're out and about in an unfamiliar place.

Taylor Derby, 19, one of those who initiated the pledge, said she was inspired in part by her recollection of a 2-year-old Rohnert Park girl who was struck and killed by a texting college student in December 2010. In the aftermath, some students signed pledges never to text behind the wheel.

"Alyssa was one of my best friends," Derby said last week, "and I don't ever want to lose somebody so close to me again."

Kevin Byrne said he and his wife decided the pledge would be a good way to use donations supporters began making when their daughter disappeared.

Derby ordered 300 hot-pink bracelets printed in memory of her friend and sold them for $3 apiece while she, the Byrnes and others worked out ideas for a larger campaign.

Casa Grande senior Sara Frazier is working with Kevin Byrne to develop a program for middle school students as part of her senior project. "I knew I wanted to do something for Alyssa," she said.

Frazier plans to visit schools and deliver bracelets and pamphlets that extol the virtues of staying safe in numbers. The pamphlets have a section where kids can fill in their friends' phone numbers or others they could call for help.

Friends have organized a benefit hip-hop concert Feb. 23 at The Phoenix Theater in Petaluma to raise funds toward the program.

"I know the word is all over the place," said concert promoter Jay Donnellan. "We're hoping for a sellout."

"It gives me a great feeling to see these kids and talk to them and (see) how they've rallied around this," Kevin Byrne said. "It's a shame it takes this kind of tragic situation, but the kids are all responding to it in a very positive way, and they're trying to learn something from it.

"And, again, they're trying to make sure this doesn't happen to anybody else."

Contributions to the "Always Buddy" program can be made through the Alyssa Byrne memorial fund at any Wells Fargo Bank branch.