Across from the elegant Millennium Biltmore hotel, Moi Williams, 59, reclines on his side, resting on an elbow on concrete steps leading to a park in the heart of downtown Los Angeles.

Rather than stand out in contrast to the business people hustling by or commuters heading home, he fits in as one of the many homeless people who idle their days in Pershing Square.

Mr. Williams’ stare is as empty as the details he offers about his life.

He said he has been on the streets three or four years. His beard and hair are starting to gray and a cigarette is propped behind his left ear.

He had a job, but “it just got away,” he told The Associated Press. He figured he would find another, but it never came along.

Now he is trying to beat drugs and alcohol.

Mr. Williams would like a place to live and some money, but said he does not stay at shelters and has not signed up for any public assistance. For now, he is mostly comfortable where he is.

A few states away, in a homeless encampment in Seattle, Tammy Stephen, 54, whose children have grown up, cooks and looks after the denizens of Camp Second Chance, a city-sanctioned encampment, as if they were her own. She has known the cycle of dependence herself and been pulled down in it by partners, she said.

Six times she has lost a place to live because her third husband got high and got them evicted.

The final time came when things started looking up. Her husband had just landed a job, but spent his first paycheck on meth and got them booted again. She went her own way at that point, but did not get sober until her third try in rehab.

She’s been homeless more than three years and has been talking with other campers about pooling money to rent a place, but it can cost $1,200 to $1,500 for tiny apartments.

At one point, she and a daughter were living in someone’s storage room for $700 a month. It was hard to afford on her monthly $734 disability payment.

“Most homeless people I know aren’t homeless because they’re addicts,” she said. “Maybe they were at one time. Most people are homeless because they can’t afford a place to live.”

In a recreational vehicle he shares with his parents and siblings in Silicon Valley’s Mountain View, the home of Google, fourth-grader John Ruiz, age 9, dreams of going to college. He knows it is the path to a better job and a home that is not on four wheels.

His father is a minimum-wage landscaper, who moved the family to the aging camper after they were evicted from an apartment where the rent kept going up, nearing $3,000 a month. His mother is five months pregnant.

The family parks the RV outside an apartment building where three-bedroom apartments rent for up to $6,000 a month.

The worst thing about living in a camper is that it is cramped, hot in summer and cold in winter. He and his brother have to walk to get water and dump their trash.

John dreams of his family having a successful life together and maybe ending up in a mansion—a home that might have a swimming pool and backyard. Or at least one big enough to have his own room.

“I want to have a happy life,” he said.

These are just three stories of the many faces who make up the over 554,000 people who are homeless in America—a figure that has gone up nearly 1 percent from 2016.

Of that total, 193,000 people had no access to nightly shelter and instead were staying in vehicles, tents, the streets, and other places considered uninhabitable. The unsheltered figure is up by more than 9 percent compared to two years ago.

Increases are higher in several West Coast cities, where the explosion in homelessness has prompted at least 10 city and county governments to declare states of emergency since 2015.

The numbers in the report back up what many people in California, Oregon and Washington have been experiencing in their communities: encampments sprouting along freeways and rivers, local governments struggling to come up with money for long-term solutions, conflicts over whether to crack down on street camping and even feeding the homeless.

Why are the numbers of those without housing on the West Coast rising?

Underlying Cause

City officials, homeless advocates, and those living on the streets point to a main culprit: the region’s booming economy.

Rents have soared beyond affordability for many low-wage workers who until just a few years ago could typically find a place to stay, as with the case of Ruiz’s parents. Now, even a temporary setback can be enough to leave them out on the streets.

“A lot of people in America don’t realize they might be two checks, three checks, four checks away from being homeless,” Thomas Butler Jr., who stays in a carefully organized tent near a freeway ramp in downtown Los Angeles, told The Associated Press.

Mr. Butler said he was in transitional housing—a type of program that prepares people for permanent homes—for a while but mostly has lived on the streets for the past couple of years.

On top of the affordability factor, the boom has also caused a shortage of available housing.

“I’ve got economically zero unemployment in my city, and I’ve got thousands of homeless people that actually are working and just can’t afford housing,” Seattle City Councilman Mike O’Brien stated in another Associated Press article. “There’s nowhere for these folks to move to. Every time we open up a new place, it fills up.”

The Sacramento Bee reported that a “$200 a month rent increase pushed Sacramento State senior Elizabeth McGuire into homelessness on a recent Sunday afternoon.

“‘Now, here I am with no money, no place to live and no car,’ she said. ‘I was really lucky because I have a good friend who said I could stay on her couch.’

“McGuire, 45, is among the 3,600 or so students at Sacramento State that campus officials estimate are homeless, based on a California State University study. The report found that one in 10 students in the system are homeless and that one in five are food insecure, according to Sacramento State spokeswoman Dixie Reid.”

The California counties of Sacramento, which includes the state capital, and Alameda, which is home to Oakland, also had one-year increases of more than 1,000 homeless people.

An August Zillow study that examined the relationship between rent increases and homelessness showed the extent of the problem. According to the real estate company: “A 5 percent increase in Los Angeles rents would lead to roughly 2,000 additional people experiencing homelessness. Rents there rose 4.2 percent over the past year.”

In addition, “In Seattle, that increase would add 258 people to the homeless population for a total of 12,498.”

“The median one-bedroom apartment in the San Francisco Bay Area is significantly more expensive than it is in the New York City metro area, and apartments in San Francisco are listed at a higher price than those in Manhattan,” The Associated Press reported.

With the combination of a shortage of housing and rising rents, it is no wonder the homeless population is skyrocketing.

Advantageous Place

Another reason homelessness is such a problem specifically on the West Coast is a result of its milder climate. Someone living on the street has a much easier time living there when it does not snow, as it does in places like New York City.

Several other factors amplify the issue, as one city in Oregon exemplifies.

“Portland is often called the City of Bridges—more than a dozen cross the Willamette and Columbia Rivers—and beneath almost all, at one time or another, one sees miserable-looking camps constructed of tents, plastic tarps, and shopping carts,” Portland native Michael Totten wrote in City Journal. “It’s impossible to avoid running into homeless people downtown, where ragged people sleep on park benches and in doorways, and where you can’t walk long without being hit up for spare change. You can hardly drive near the city center without encountering men or women holding up cardboard signs asking for money at an intersection.”

“Portland is a better place to be homeless than most American cities,” Mr. Totten further stated. “The weather is mild, the citizens are generous—Portlanders spend millions yearly in private donations and tax dollars trying to help the homeless—and public officials are blocked by the courts from regulating vagrancy in ways that are routine elsewhere. Some homeless actually move to Portland from other cities. Homelessness is so visible here that it has encouraged not only expansive nonprofit relief efforts, some of which seem to be doing real good, but also, in at least one case, an innovative approach that may truly ease the problem—and that other cities might consider adopting.”

The same applies to the states of Washington and California, where homeless programs are commonplace.

The overall homeless population in California, Oregon and Washington grew by 14 percent over the past two years, and the part of that population considered unsheltered climbed 23 percent to 108,000.

In booming Seattle, for example, the HUD report shows the unsheltered population grew by 44 percent over two years to nearly 5,500.

The homeless service area that includes most of Los Angeles County, the epicenter of the crisis, saw its total homeless count top 55,000 people, up by more than 13,000 from 2016. Four out of every five homeless individuals there are considered unsheltered, leaving tens of thousands of people with no place to sleep other than the streets or parks.

By comparison, while New York City’s homeless population grew to more than 76,000, only about 5 percent are considered unsheltered thanks to a system that can get people a cot under a roof immediately.

Everyday Living

The surge in homelessness has become part of the fabric of daily life on the West Coast.

The Monty, a bar in the Westlake neighborhood near downtown Los Angeles, usually does not open until 8 p.m. Partner and general manager Corey Allen said that is because a nearby shelter requires people staying there to be in the building by 7. Waiting until after that to open means the streets outside are calmer.

Mr. Allen said the homeless have come into his bar to bathe in the restroom wash basins, and employees have developed a strategy for stopping people from coming in to panhandle among customers.

Seventy-eight-year-old Theodore Neubauer sees the other side of it. Mr. Neubauer says he served in Vietnam but now lives in a tent in downtown Los Angeles. He is surrounded by thriving business and entertainment districts, and new apartments that are attracting scores of young people to the heart of the nation’s second most populous city.

Excluding the Los Angeles region, total homelessness nationwide would have been down by about 1.5 percent compared with 2016.

Portland recently saw the implementation of a pilot program that offered homeowners a free tiny house if they let someone homeless live in it for five years. And popular clothing company Columbia Sportswear is considering moving its headquarters from downtown Portland to another location after employees reported multiple car break-ins, garbage and human waste left at their front door.

Health Implications

The most alarming consequence of the West Coast homeless explosion is a deadly hepatitis A outbreak that has affected Los Angeles, Santa Cruz, and San Diego, the popular tourist destination in a county where more than 5,600 people now live on the streets or in their cars. The disease is spread through a liver-damaging virus that lives in feces.

The outbreak prompted California officials to declare a state of emergency in October.

Surprisingly, in contrast to the high numbers nationwide, the HUD report showed a long-running decline in homelessness continuing in most other regions. Nationally, the overall homeless number was down by 13 percent since 2010 and the unsheltered number has dropped by 17 percent over that seven-year span, although some changes in methodology and definitions over the years can affect comparisons.

Places where the numbers went down included Atlanta, Philadelphia, Miami, the Denver area, and Hawaii, which declared a statewide homelessness emergency in 2015.

This article contains information from The Associated Press.