Students and teachers are dealing with some combination of in-person and remote classes, knowing that everything could change with one positive COVID test. Restaurants created online to-go services out of thin air, and turned sidewalks and streets into welcoming patios.

Every day during the coronavirus crisis, people, businesses and institutions are being asked, on the fly, to change what they do and how they do it. It’s the only way to deal with something nearly all of us have never experienced before.

But the Cumberland County commissioners apparently haven’t gotten the memo yet.

The commissioners Monday voted 5-0 against allowing the city of Portland to use the Cross Insurance Arena as a temporary emergency shelter for the homeless.

In doing so, they took sides with the trustees of the publicly owned arena, who earlier cited contractual, logistical and insurance-related problems in refusing the city’s request.

Portland’s mayor and five city councilors wrote a letter to commissioners pleading for time to work through the issues, but they rejected that, too.

This is an opportunity for the county to help its largest city out of a bind caused by COVID-19, and to take some responsibility for the regional problem of homelessness. The commissioners blew it, and they should reconsider.

In Portland, which has the state’s largest homeless population, services have been stretched thin since the coronavirus forced Preble Street, a nonprofit social service agency, to close its Resource Center and the city to reduce its shelter capacity.

The changes cut back on services and put more people on the streets, leading to the two-week protest camp outside Portland City Hall that ended in August.

A temporary shelter placed at the University of Southern Maine closed in July so the school could prepare for the upcoming year, while another at the Portland Expo will close soon as a result of its contract with the Maine Red Claws basketball team.

City officials say they are left without other adequate sites, leaving dozens of Mainers without a place to go heading into winter. At the same time, the untreated mental illness and substance use disorder and the lack of affordable housing that are driving homelessness are being made worse by the crisis and accompanying economic devastation.

No one can sure how the next few months will look for some of Maine’s most vulnerable residents.

First and foremost, homelessness requires statewide and national solutions to create more affordable housing and put care where it is needed most.

But in Maine, it is also a regional problem, though Portland and other cities are usually left to deal with it on their own. The pandemic has only highlighted how Maine needs a new approach to homelessness.

Allowing the arena, which will otherwise sit empty for the foreseeable future, to be used as a temporary shelter would be a good way to show that the county wants to be part of the solution.

It would also show that the county is a good partner in an emergency, ready to be flexible in order to solve the kind of once-rare problems that are surfacing now every day.