It may mean a break with family traditions, but celebrating Thanksgiving dinner or Christmas outdoors this year could be the best thing to prevent the spread of COVID-19. The weather just needs to cooperate.
A long-term forecast from the National Oceanic and Atmospheric Administration predicts winter in North Texas will be warmer and drier than usual. If that holds true — and North Texans adjust their behavior — a surge in coronavirus cases could be prevented, says Dr. Edward Nardell, a professor at Harvard Medical School and a professor of environmental health and immunology and infectious diseases at the Harvard T.H. Chan School of Public Health.
Over the summer, many Southern states, including Texas, saw a dramatic rise in the number of COVID-19 cases. In July, Dallas County recorded more than 1,000 new cases a day for 18 consecutive days.
Nardell suggested one reason cases surged in the South was that people were spending more time indoors where there was air conditioning. Things could be flipped in the winter, he said, if a milder winter lets people spend more time outdoors.
“I think, yes, it will reverse,” Nardell said. “Both scenarios are true.”
Studies have shown that the risk of contracting COVID-19 is significantly lower outdoors. One study in Japan concluded the chance of catching the virus is 20 times greater indoors.
To explain why, Nardell suggested imagining a cloud of cigarette smoke.
A puff of smoke is likely to disperse faster outdoors than in a poorly ventilated space. The longer the smoke lingers, the greater the chance someone will inhale it. Nardell said the same is true for aerosols, or particles that contain the coronavirus.
“Outside it has the best chance of getting dispersed,” he said. “To get infected, it appears as though you really need to get into one of those clouds. The role of ventilation is to disperse that cloud.”
The longer someone is around that cloud, Nardell said, and the more the person inhales, the likelier the person is to get an “infectious dose” of the virus.
A behavioral aspect
A mild winter isn’t a cure-all. People’s behavior will also play a role in whether cases surge during the winter.
“If people are on their patios, that’s great, but face-masking is important,” Nardell said. “Outdoors is best — distance, still.”
Nardell said being outdoors doesn’t help much if people are shoulder to shoulder without masks on.
“It isn’t automatic,” he said. “There’s the behavioral aspect.”
Dallas County Judge Clay Jenkins has stuck with the message of social distancing and wearing masks. But as temperatures have dropped in North Texas, he has also urged residents to stay outdoors whenever possible.
“If you choose to eat at a restaurant, consider patio dining,” Jenkins said Monday in a written statement. “If you choose organized workouts, consider working out outside the building in the fall weather and not inside of an indoor facility with heavy breathing and without masks.”
Similarly, the Public Health Committee is strongly encouraging people to take advantage of the cooler weather and do more workouts and other activities outside rather than in indoor locations.
— Clay Jenkins (@JudgeClayJ) September 23, 2020
Nardell strongly recommended that people tweak their holiday traditions to match the conditions of the pandemic. Thanksgiving dinner should be moved to the patio, especially if people invite others over.
“Homes are designed for comfort, not for infectious-disease prevention,” he said. “The other [option] is don’t do it this year.”
NOAA forecast
Of course, plans for al fresco holidays may depend on the forecast for a warmer winter coming true.
A number of factors went into NOAA’s long-term prediction. One of the most important was the expected formation of a La Niña, in which surface temperatures in parts of the Pacific Ocean drop lower than normal. A La Niña usually means a drier and milder winter for Texas and much of the rest of the South.
Long-term forecasts predict climate trends but not day-to-day weather, which means Dallas-Fort Worth could see some serious cold snaps, perhaps just not as frequently, said Patricia Sanchez, a National Weather Service meteorologist.
“It doesn’t mean we won’t see those cold outbreaks, [and] it doesn’t mean it’s going to be dry.”
