During the last government shutdown, in January, rangers weren't readily available to clear trees downed across a road to the Hoh Valley at Olympic National Park/NPCA

With concerns growing that the federal government will shut down, at least partially, late this week, the question of whether the National Park System will be open to visitors is a natural one. The answer is yes, but with some caveats.

If government does close, most National Park Service employees will be sent home, or furloughed, for the duration of the closure. Key personnel, such as law enforcement rangers and those needed to keep the power on to buildings will remain on the job. Concessions will continue to operate, and visitors will be free to enter.

"Parks must notify visitors that the NPS will cease providing visitor services, including restrooms, trash collection, facilities and roads maintenance (including plowing), campground reservation and check-in/check-out services, backcountry and other permits, and public information" in the event of a shutdown, according to the contingency plan the Park Service adopted last January. "While parks may still be accessible to visitors, parks may not use the presence of visitors in the park to justify higher staffing numbers than approved during previous shutdowns."

If conditions -- snowstorms, torrential rains, wildfires -- create risks to visitors, affected areas "must" be closed, the document says.

Additionally, park websites and social media channels will not be maintained during the shutdown.

"At the superintendent’s discretion, parks may close grounds/areas with sensitive natural, cultural, historic, or archaeological resources vulnerable to destruction, looting, or other damage that cannot be adequately protected by the excepted law enforcement staff that remain on duty to conduct essential activities," the document says.

Not too many years ago the park system closed to visitors during government shutdowns. That became a huge issue during the shutdown in October 2013, when some states that enjoy peak tourism during the fall months put up the money to keep certain parks open rather than take an economic impact to surrounding communities. In the end, the states did take a hit, as the federal government never repaid them for the millions of dollars they spent keeping the parks open.

The face of the 2013 closure, if you will, in many instances was the National Park Service, as river trips and weddings were canceled and vacations interrupted.

The policy of closing parks during government shutdowns ended in January 2018, when the Trump administration made the decision to keep them open. There was some conjecture that a government shutdown was the perfect opportunity for the Trump administration to show Congress and the American public that parks can be run effectively without the NPS.

Not everything rolled smoothly, though. At Zion National Park in Utah a cow elk was poached inside the park during last January's shutdown. At Olympic National Park in Washington, roads were blocked by trees that a storm downed.

Back in 1995, Arizona's governor sent out the National Guard to keep Grand Canyon National Park open during a government shutdown.