The Centers for Disease Control and Prevention is expected to issue new guidelines aimed at preventing parks from becoming viral hotspots as the novel coronavirus continues to spread and Americans seek time outside as a break from staying at home.
The National Park Service, as well as state and local recreation departments, have closed some parks or areas of parks to protect visitors and staff from coming in close contact with one another -- but in many national parks, outdoor spaces have remained open.
Vice President Mike Pence said that new guidance will be released by CDC as many fear that these areas -- which have seen a surge of visitors in the last few weeks -- could become breeding grounds for the coronavirus.
“It would be several weeks ago that our park service waived all entrance fees and we directed the CDC to provide us guidance for how people can still practice social distancing and common sense but be out of doors and enjoy our natural parks. We will be sharing our guidance with state park systems around the country and encouraging their support,” Pence said.
Despite instructions from federal, state, and local officials to stay at home and avoid crowds some parks have noted that people continue to visit parks in large numbers, gathering in parking lots, bathrooms, and popular spots despite guidelines to maintain a social distance from other people. Cities like Washington, DC and Chicago have also closed popular public areas saying crowds are not practicing social distancing.
Officials have also raised concerns that even while outside, large crowds still pose a risk of increasing exposure to the COVID-19 virus.
"We are concerned that current visitation patterns are not meeting current CDC guidance on social distancing," Zion National Park staff wrote on instagram.
"If you are coming to the park, please choose to visit areas that are not crowded to allow for adequate social distancing," they said.
The National Park Service has said it is adapting operations to the latest CDC guidance and making decisions about closures on a park-by-park basis, but that outdoor spaces will remain open as long as they can comply with social distancing.
Advocates and former Park Service employees have criticized the administration's decision to waive entrance fees and encourage people to visit parks, saying there should have been more direct guidance earlier to close parks or direct people to less popular areas to prevent crowding.
Kevin Dahl, Arizona senior program manager for the National Parks Conservation Association, said he's hearing of the usual spring break crowds at Grand Canyon National Park, where local communities have called for the park to close, but the state is not under a shelter-in-place order like other parts of the country.
He said the best thing to do would be to close the Grand Canyon and other popular parks and redirect people who want to get outside to other public lands that are more spread out.
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"It would be so much better if the federal government could do what it should do and manage these places in a way that people know they're safe when they're going there," Dah told ABC News. "The South Rim of the Grand Canyon is no place to be right now."
Park Service spokesperson Alex Picavet said no decision has been made about whether they will close Grand Canyon National Park.
An Interior Department spokesperson said the National Parks Service is working closely with local health officials to decide what changes need to be made to national park operations and that the department would follow any additional CDC guidance.
ABC News' Elizabeth Thomas contributed to this report.