“It’s going to be a hard and tough winter,” Whatley said. “As you see outdoor dining not being feasible from a cold-weather perspective or, unfortunately, from a government regulations perspective, you are going to see more operators going out of business.”

In recent months, many cities and states have imposed a raft of restrictions on indoor dining, given the high risk of spreading the virus in these crowded settings.

Many have capped occupancy for dine-in restaurants. Some halted indoor dining altogether, including Michigan and Illinois. Others have gone even further. Los Angeles and Baltimore have halted indoor and outdoor dining. Only carryout is allowed.

Those who can serve customers outdoors, on patios or sidewalks, are coming up with creative adaptations that can make dining possible in the frigid depths of winter.

Embrace the ‘Yurtiness’

Washington state shut down indoor dining in mid-November and has kept that ban in place as coronavirus cases continue to surge.

On a blustery December evening, servers at the high-end Seattle restaurant Canlis huddled together in the parking lot, clad in flannel and puffy vests, while their boss Mark Canlis gave a pep talk ahead of a busy night.

“The hospitality out here is exactly the same as it is in there,” Canlis said, gesturing to his restaurant, which overlooks Lake Union. “But that looks really different, so try to invite them into the ‘yurtiness’ of what we are doing.”

Canlis has erected an elaborate yurt village in the parking lot next to his family’s storied restaurant.

It includes an outdoor fireplace and wood-paneled walkways winding between small pine trees and the circular tents. The assemblage of yurts, with their open window flaps, is the Canlis family’s best effort to keep fine dining alive during the pandemic and a typically long and wet Seattle winter (referred to locally as the “Big Dark”).

Arriving guests are greeted with a forehead thermometer to take their temperature and a cup of hot cider.

“It gives us an excuse to think differently,” Canlis said of the outdoor dining restrictions.

The yurts are meant to shield diners from the elements and from infectious airborne particles that might otherwise spread from table to table.

Dining inside such structures is not risk free: Guests could still catch the virus from a dining companion as they sit near each other, without masks, for a prolonged period. But Canlis said there is no easy way to determine whether every member of a dining group is from the same household.

“I’m not the governor or the CDC,” he said. “I’m assuming if you are there at the table, you’re taking your health into your own hands.”

New rules for outdoor dining structures in Washington require Canlis to consider issues such as how to ventilate the yurts properly and sanitize the expensive furniture.

“What is the square inch of yurt volume space? What is the size of the door and the windows? How many minutes will we allow the yurt to ‘breathe?'” Canlis said.

The structures get cleaned after each dining party finishes a meal and leaves; during the meal service the waiters enter and leave quickly, wearing N95 masks.

Igloos, Domes, Tents: Just How Safe Are They?

Another, more modern-looking take on outdoor dining involves transparent igloos and other domelike structures that have become popular with restaurant owners all over the country.

Tim Baker, who owns the Italian restaurant San Fermo in Seattle, had to order his igloos from Lithuania and assemble them with the help of his son.

His restaurant’s policy is that only two people are allowed in an igloo at a time, to cut down on the risk of those from different households gathering together.

“You’re completely enclosed in your own space with somebody in your own household. These domes protect you from all the people walking by on the sidewalk, and the server doesn’t go in with you,” he said.

Baker said he consulted with experts in airflow and decided to use an industrial hot air cannon after each party of diners leaves the igloo and before the next set enters — aiming to clear the air inside the structure of any lingering infectious particles.

“You fire this cannon up, and it just pushes the air through really aggressively,” quickly dispersing the particles, Baker said.

His restaurant’s igloos have become a big attraction.

“I’m particularly proud of anything that we can do to get people excited right now, because we need it,” he said. “We’re all getting crushed by this emotionally.”

Not all outdoor dining structures are created equally, said Richard Corsi, an air quality expert and dean of engineering and computer science at Portland State University in Oregon.

“There’s a wide spectrum,” Corsi said. “The safest that we’re talking about is no walls — a roof. And then the worst is fully enclosed — which is essentially an indoor tent — especially if it doesn’t have really good ventilation and good physical distancing.”

In fact, Corsi said, some outdoor dining structures that are enclosed and have lots of tables near each other end up being more dangerous than being indoors, because the ventilation is worse.

Dining that is truly outdoors, with no temporary shelter at all, is much safer because there are “higher air speeds, more dispersion and more mixing than indoors,” Corsi said, which means respiratory droplets harboring the virus don’t accumulate and are less concentrated when people are close to one another.

“If they have heaters, then you’re going to actually have pretty good ventilation,” Corsi said. “The air will rise up when it’s heated, and then cool air will come in.”

He said private “pods” or “domes” can be fairly safe if they are properly ventilated and cleaned between diners. That also assumes that everyone eating inside the structure lives together, so they have already been exposed to one another’s germs.

But Corsi said he is still not going out for a meal in one of the many new outdoor dining creations — “even though I know they’ve got a much lower risk” of spreading covid-19 than most indoor alternatives.

This story comes from NPR’s health reporting partnership with Kaiser Health News.