Oregon Gov. Kate Brown announced a new mask requirement for outdoor activities.

The order, which goes into effect Friday, applies to all residents regardless of vaccine status during "outdoor settings in which individuals from different households are unable to consistently maintain physical distance."

"The rule does not apply to fleeting encounters, such as two individuals walking by one another on a trail or in a park," the governor's office said in a news release.

Outdoor gatherings in private residences are also exempt.

Brown cited the growing number of COVID-19 cases in the state fueled by the delta variant as the motive behind the rule.

The U.S. Centers for Disease Control and Prevention revealed new COVID-19 forecast models Tuesday that showed daily hospitalizations could more than double by mid-September.

By Sept. 20 the U.S. could see hospitalizations as high as 27,000 a day, according to the agency's models. Currently the seven-day average of COVID-19 related hospitalizations is 12,190, according to the CDC.

The peak seven-day average was 16,492 in January, according to health data.

The low-end of the CDC's forecast's models is 7,800 hospitalizations a day.

Health officials stress that a change in behavior, including masking, vaccination and social distancing, will reduce severe illness and hospitalization.

-ABC News' Brian Hartman

There are currently no COVID-19 intensive care unit beds available in the state of Arkansas, a situation Republican Gov. Asa Hutchinson referred to as a "cautionary note for everyone" Tuesday.

"It fluctuates day by day. But right now, because of the increased number of COVID patients that need that type of ICU care, those beds are full," Hutchinson told reporters.

There are still ICU beds available for non-COVID patients, Hutchinson noted.

Arkansas lags behind the national average in vaccinations. As of Monday, 52% of residents had received at least one dose, and 40% were fully vaccinated, according to the Centers for Disease Control and Prevention. By comparison, 61% of Americans have gotten at least one shot and 52% are fully vaccinated.

-ABC News' Libby Cathey

Dr. Francis Collins, director of the National Institutes of Health, said he expects children ages 5 to 11 in the United States to become eligible for COVID-19 vaccination toward the end of the year.

"Keep in mind, kids are not just scaled down adults -- they have different immune systems and metabolisms. You really have to do the careful trials to make sure you got the dose right and there aren't any surprises," Collins told ABC News' George Stephanopoulos in an interview Tuesday on "Good Morning America."

"Realistically," he added, "I don't think we're going to see approval for kids under 12 until late in 2021."

Collins also said there is “no reason to be too confident” that the country has hit its peak and that case numbers will start to come down.

"When I look at the data, it's still going up awfully steeply. More than 150,000 cases a day and that number keeps growing; hospitalizations [at] 95,000; deaths now averaging a 1,000 a day," he noted. "Florida, Louisiana, Mississippi, Alabama -- there's just a world of hurt going on there with so many unvaccinated people and hospitals really struggling to try to manage all the really sick people who are coming to their emergency rooms."