The shelters in New York were full. Now they are bursting at the seams.

In 2021, New York’s shelter system was under pressure, with a population of 61,000. Officials said it was full – or more.

By 2023, the system is on track to house twice as many people.

The population reached an eye-popping record of 100,000 this week, thanks to familiar factors – the pandemic, skyrocketing rents – and acute: economic unrest abroad and politicians in America trying to plunge New York thousands of miles away into a border crisis.

Due to the large influx from the south, people not only live in traditional shelters, but also in temporary shelters in hotels, tents and even gymnasiums. The Roosevelt Hotel, which opened to fanfare in Midtown in 1924 and where annual New Year’s Eve radio broadcasts popularized “Auld Lang Syne,” will hand over all 1,000 rooms to migrants in the coming months.

Officials described this week as a “tipping point” – for the first time, migrants made up the majority of those in shelters. The surprising new number of asylum seekers is further disturbing because of the numbers it does not reflect.

“It’s frightening that we’re on this metric and we don’t even know how accurate it is, how many are missing,” said Adolfo Abreu, director of housing campaigns at Vocal-NY, a social services agency.

Such an explosion of migrants, estimated to cost $4.3 billion by July 2024, would test every American city. In New York, the arrivals were met by a system that was already under strain from factors brought on by the city itself.

New Yorkers are spending more on rent than ever. And when they can no longer pay, lose their home and exercise the city’s unique right to shelter, they find it harder than ever to find affordable permanent housing. So they stay longer in the facilities than previous generations – the average stay for families with children is more than 530 days, according to the most recent figures, double from 15 years ago.

More homeless people compete for homes, until the shelter becomes the home.

In 2022, the floodgates opened when a bus arrived from Texas with only 40 people. It was received by emergency workers with blankets and the handshakes and cheers of a city that prided itself on performing.

The applause stopped and the cameras panned elsewhere, but the buses – and planes – kept coming. Shelters opened faster than pop-up restaurants, more than 170 since last spring, sometimes overnight.

“There isn’t a day when I go to bed and I don’t think, ‘Have we got enough for tonight?'” said Anne Williams-Isom, deputy mayor for health and human services.

Where do those 100,000 people live? What does that life look like?

Renee Culp, 50, has been in shelters for ten years. “It’s been hell,” she said. “You have no resources.” Try to find a job without a computer to look for one, she said.

A more recent arrival is Elliot Ramirez, 36, a Colombian carpenter who left his family behind and traveled through Nicaragua and Mexico to swim the Rio Grande to Texas. He said a “foundation” gave him a free plane ticket and he spent two months at the Bedford-Atlantic Armory shelter in Brooklyn.

It’s been a whirlwind. The food is ok. It’s uncomfortably busy, although so many people speak Spanish that it reminds him of home. Jobs are hard to come by without a work visa, so he can’t use the skills he brought with him.

“It’s more complicated in New York,” he said.

Roger Davis, 65, entered a shelter in the Bronx after a street worker found him sleeping on a subway. He lived indoors for a year until it got too crowded. No one seemed to follow the rules anymore and smoked wherever they wanted. The bathrooms became filthy and exhausted employees were berating everyone in front of them.

Mr. Davis returned to the street. Sometimes he sleeps on the subway, sometimes on the sidewalk, in huts made from shipping pallets.

“It’s easier that way,” he said.

Ezekiel Lee, 57, at a shelter on 12th Street in Brooklyn, said there’s more trash in the system — razors that have been used once and thrown away, leading to a shortage.

He said the arrival of migrants in such numbers – “and don’t get me wrong, I’m sympathetic” – puts a strain on the system. “It’s not one thing,” he said. “It’s a lot of different things.”

Put another way, “This is a humanitarian crisis,” said Christine Quinn, the former New York City Council speaker who now heads the Women In Need shelter. “If there’s a goddamn roadblock, get over it.”

Mr. Abreu of Vocal-NY said the population of 100,000 is unlikely to shrink any time soon.

“Many of us are one income shock away from being homeless,” he said. “That’s a very precarious situation that, if we don’t dig, could double or triple the 100,000.”

Nate Schweber And Olivia Bensimon reporting contributed.