Mayor Michael Hancock on Wednesday described a city on the verge of running out of resources to meet the challenges of an influx of migrants from the southern border coupled with a dangerous arctic cold front expected to grip a wide swath of the country over the next few days.

More than 1,300 migrants from the southern border have arrived in Denver since Dec. 9, according to an update from the city’s Office of Emergency Operations on Tuesday night. More are likely on the way, arriving daily via buses and other forms of transportation. The city is operating two shelters in undisclosed city facilities to accommodate those people, Denver’s chief housing officer, Britta Fisher, said, as well as working with partner organizations to house dozens more.

With temperatures expected to plunge below zero in the city on Wednesday night, accompanied by wind chill factors as cold as minus 25, the city also opened the Denver Coliseum as an emergency 24/7 shelter starting at 3 p.m. Wednesday.

“Not only are we worried about people being outdoors during this time but we are at a breaking point in terms of resources and ability to accommodate people,” Hancock said.

Hancock has spoken to the mayors of 10 other cities across the country also concerned about their ability to shelter people during the dual crises of incoming migrants and arctic cold, he said.

“So we’re all raising the red flag. That’s why we’re all talking to various counterparts across the country, as well as the White House and members of our congressional delegation,” he said. “It’s not just Denver. As the … arctic blast goes across the nation, cities like Chicago, New York and Minneapolis, who are also seeing a surge of migrants, are also saying the same thing.”

Hancock’s remarks came as part of a news conference Wednesday morning in the basement of the city and county building, where the city’s emergency operations center is housed. The center was activated in response to the sudden arrival of hundreds of migrants in Denver last week. During Wednesday’s conference, city officials said the coliseum shelter would have 225 beds. Fisher acknowledged that may not be enough and additional shelter spaces were being explored.

By Wednesday afternoon, the city followed up to announce that the downtown YMCA, at 25 E. 16th Ave., would also open as a 24-hour emergency shelter starting at 7 a.m. Thursday. That facility should have room for an additional 100 people and is expected to remain open until noon Saturday.

During a media tour of the coliseum before its opening Wednesday, city spokeswoman Jill Lis said the facility had enough cots for 275 people. The cots and tables for eating and gathering were spread around the main concourse of the building.

The arena floor is not being utilized for shelter space because crews are in the process of setting up for next month’s National Western Stock Show.

The coliseum shelter is expected to remain open at least until Saturday. People will be given cots on a first-come, first-served basis. Those who leave will not be able to hold space there. If beds are full when people arrive, the city will allow them to come in and stay warm until alternative shelter can be arranged for them, Lis said.

Silray McGee, 60, was among about a dozen people who gathered outside the coliseum’s front entrance more than an hour before it opened Wednesday. A 40-year resident of Denver, he’s experiencing homelessness for the first time in his life, he said, but he knows that lines for overnight shelters get long, which is why he showed up early.

“They’ve got buses dropping off people,” he said. “So, depending on how late that is, you could be freezing out here.”

McGee heard about the coliseum while at a day shelter downtown Tuesday, he said. He knows some people won’t come to a shelter regardless of how dangerous the weather conditions might be.

“Some people don’t want to come inside because of mental health issues or drug addiction,” he said. “Or just people being hard-headed and not listening to the weather.”

The Colorado Coalition for the Homeless was set to host its annual homeless persons’ memorial vigil on the steps of the city and county building starting at 5 p.m. Wednesday.

Coalition spokeswoman Cathy Alderman said the memorial, being held to honor the memories of unhoused people who died on the city’s streets in the previous year, would go forward as planned in spite of the weather but may wrap up early.

Fisher mentioned the vigil in her comments Wednesday. She noted that at least 260 people would be memorialized at the event, some of whom died from exposure to the elements.

“It’s a reminder of how important our efforts are to encourage everyone to come inside,” she said.

The city has declared a state of emergency and extended it for the migrant crisis, a step that opens up more state and federal financial resources and gives the city greater spending flexibility to respond to needs.

Hancock estimated Denver has spent $2 million providing shelter and other needs for the people who have arrived here.

As of Tuesday, 470 migrants were staying in city shelters and an additional 192 were being sheltered by the city’s partner organization. On Tuesday, the city applied for $1.5 million in reimbursement from the state for expenses incurred during the crisis.

But longer-term solutions are needed, in Washington when it comes to immigration reform and locally when it comes to shelter space, Hancock said.

“I think it’s important to note these are temporary measures. We cannot lock down the coliseum on a permanent basis, and you can’t lock down these recreation centers on a permanent basis,”

He said. “We’re already working and talking about how we transition from these temporary shelter facilities today because we’ve got to get them back online.”

In a news release Tuesday, officials said the city started providing free buses from the Denver Rescue Mission’s Lawrence Street Community Center, 2222 Lawrence St., to the coliseum Wednesday afternoon. Walk-ins and drop-offs also will be welcome. There will be parking for those who bring vehicles to the arena, at 4600 Humboldt St., officials said.

Registered service animals will be allowed inside the coliseum, but pets will not be, the city said. Denver Animal Protection officials will be available to transport pets to the city’s animal shelter for temporary housing.

Denver libraries and recreation centers will be available for those seeking refuge from the cold during those facilities’ regular business hours Thursday and Friday, according to the city.

Rob and Kate Mays waited outside the coliseum before it opened Wednesday with their pit bull-Mastiff mix Shady. Shady is a service animal, they said.

The couple did not expect to need shelter from the cold front.

They were staying at a motel when Rob’s company card from his job at Amazon stopped working and they could no longer pay for their room, they said. With nowhere to go while waiting for their finances to be figured out, a Denver police officer suggested the coliseum and drove them there.

They didn’t know what they might have done to keep warm otherwise.

“We’ve done our share of camping but not like this. Not with nothing and no way to get anything,” Kate said.

She called the coliseum a fantastic last-minute option but added “it would have been great to not need it at all.”