The faces of Palo Alto's and Santa Clara County's homeless residents are getting older, as more seniors are unable to afford the region's skyrocketing rents, members of a panel on homelessness said on Thursday.

The panel of experts, which was moderated by Santa Clara County Supervisor Joe Simitian, spoke during the "Faces of Homelessness in Silicon Valley: Perception versus Reality" luncheon at the Crowne Plaza Hotel.

The event was organized by LifeMoves, formerly InnVision Shelter Network, the largest nonprofit agency serving homeless individuals and families in Santa Clara and San Mateo counties. Panelists were Jennifer Loving, executive director of Destination: Home; Kevin Fagan, San Francisco Chronicle reporter; and Brian Greenberg, LifeMoves vice president.

The threat of homelessness is on the rise nationwide, as service and lower-wage workers are being pushed out of housing because of the disparity between wages and housing costs, the panelists said. The Bay Area's exceptionally high housing costs have exacerbated the situation, which is also playing out in Palo Alto.

Greenberg, who is also a psychologist, found that many of Palo Alto's homeless population at the Opportunity Center's Drop-in Center were once housed residents.

"I was amazed at the number of people that went to Paly and Gunn (high schools). So many people that grew up in middle- and upper-middle-class families," he said.

Families and seniors are the rising homeless populations, the panelists said.

Santa Clara County has the highest per capita of physically unsheltered population in the United States, even though there are six or seven jurisdictions nationally that have larger numbers of homeless, Loving said.

There are 6,500 homeless persons on Santa Clara County streets each night, but the bad news is that it is probably an undercount, she said. About 30 percent of homeless persons in Santa Clara County are living on the street without shelter every day, Simitian added.

LifeMoves has 17 facilities to help homeless individuals and families, with six of the facilities serving families alone. Up to half of those families come with a head of household who is working one or two jobs, Greenberg said.

Seniors make up the most rapidly growing population showing up at LifeMoves shelters, Greenberg said, and many have health-related challenges.

"Some of our shelters look like senior-care homes. And unlike many common perceptions about the homeless, these people, many of them, have no history of mental illness; have no history of addiction. They were living in a Mountain View apartment or a Redwood City apartment, and 10 years ago their one-bedroom rent was $800, now it's $2,600. They have no local family and they wind up in shelters. So the face of homelessness is suddenly changing with the times," he said.

"The housing crisis feeds homelessness," added Fagan, who has reported extensively on the issue.

In San Jose alone, there are more than 300 homeless encampments, Loving said.

"There is not a city in this county that doesn't have a problem with encampments along waterways, parks, parking garages and alleys," she added.

San Jose had the largest homeless encampment in the county known as "The Jungle." Before it was closed, Loving spent a year there working with teams of doctors and organizations to help connect people to housing and services.

"It was horrifying. ... Some of the most heartbreaking things I saw in The Jungle were the kids that were coming out of the tents ... and (put on) their backpacks to go to school. Some of the girls were my daughter's age," she said.

Greenberg said breaking the cycle of homelessness is difficult, but he pointed to cities that have seemingly "cracked the code," including Salt Lake City, Utah, and Cleveland, Ohio. Those cities have one-bedroom apartments for under $600 per month, compared to Redwood City's average of $2,500 per month, he said.

When one looks at all of the problems that contribute to homelessness, the common element is that people don't have a home, Loving said. "Housing-first" programs, with multiple supportive services to address physical and mental health, addiction and joblessness, have dropped the county's costs for managing homelessness because people are not sick, hurt or dependent anymore, she said.

During 2015, LifeMoves, which manages Palo Alto's Opportunity Center Drop-in Center, provided services to more than 15,000 people in Santa Clara and San Mateo counties, and helped 1,000 homeless families and individuals each night in 17 locations, according to the organization.

While receiving interim housing, clients receive behavioral, career, financial, health and learning services to break the cycle of homelessness. Ninety-seven percent of families and 82 percent of individuals in interim housing who completed LifeMoves programs returned to stable housing and self-sufficiency, the organization said.

Loving said that programs such as Destination: Home and LifeMoves aided in reducing the number of homeless people in Santa Clara County. The number is the lowest in 10 years, she said. In 2011, the county began an aggressive program to reduce homelessness. In 2013, the county had an estimated 7,600 homeless persons; by 2015, the number dropped to 6,500, she said.

Chronicle reporter Fagan, who lived among San Francisco's homeless for six months and reported extensively on their conditions, said that housing-first programs have dramatically reduced the cost of caring for chronically homeless persons. On average, a chronically homeless person costs $60,000 annually in city services such as repeat police calls and hospital visits, he said. But a homeless person in supportive housing costs $15,000-$20,000 per year.

"We're turning the tide, finally, in our community," Loving said. "Homelessness is a justice issue and homelessness is one of responsibility. ... But no one is actually responsible because if you are responsible, you do something about it -- you solve it.

"We locally have started to take responsibility in a really meaningful way over the last five years, I'd say. We're really saying, 'This is our problem and we're gonna fix it.' And that's why we're seeing numbers start to go down."