Visitation to the 401 units of the National Park System last year slipped to 273.6 million, a drop of 9.1 million visitors from the 282.7 million counted in 2012.

The dip, a bit more than 3 percent, was not unexpected, due to a variety of factors. As we noted earlier this month, nasty weather, sequestration impacts, government shutdowns all combined in 2013 to drive down visitation.

Superstorm Sandy, which slugged its way up the East Coast in November 2012, inflicted a lot of damage that kept some units -- such as the Statue of Liberty, Ellis Island, Fire Island National Seashore, parts of Gateway National Recreation Area -- closed months into 2013.

The Washington Monument, which typically is visited by more than 600,000 people a year, was closed throughout 2013 while engineers inspected it for damage (and repairs got under way) stemming from a 5.8 magnitude earthquake in 2011. Ice and snow storms early in 2013 at various times shut down the Skyline Drive through Shenandoah National Park and the Blue Ridge Parkway. Yosemite National Park visitation suffered a bit from the Rim Fire.

Butch Street, the Park Service's visitation statistician, said Thursday that tracking down missing park data and correcting errors in initial reports led to the improvement in year-end visitation over what he had predicted earlier in the month.

"There were a lot of parks that had bad data, and it always happens every year. And the other part, I had a number of parks that didn’t report at all (when the earlier estimate was made)," he said.

At the same time, he attributed much of the drop over 2012 levels to the partial government shutdown in October. 

“6.4 million (down) in October," noted Mr. Street.

Officials in the National Park Service's Washington office are planning to discuss the 2013 numbers, as well as the economic impact of the National Park System, on Monday.

Looking at some visitation categories, backcountry use in the park system in 2013 recorded 1.7 million visitors, down from 1.81 million the year before. Recreational vehicle overnight stays were off, dipping from 2.12 million in 2012 to 1.97 million last year. Also down were tent campers, from 3.2 million in 2012 to 2.99 million last year.

Rocky Mountain National Park was handed a double-whammy in 2013, with flooding in September that washed out two highways that funnel visitors to the park, and then the October shutdown. While the park saw 2012 visitation reach 3.2 million, it dipped to 2.99 million in 2013, with September visitation down almost 50 percent (527,171 vs. 253,467) and October visitation off by two-thirds (219,946 vs. 66,275).

Statue of Liberty National Monument's 2013 visitation of 1.88 million was far off the pace of 2012, when 3 million visitors toured the grounds of the iconic statue. Along the Blue Ridge Parkway, which struggled with weather problems early in the year as well as the October shutdown, 2013 visitation stood at 12.87 million, down from 15.2 million in 2012.

At Great Smoky Mountains National Park, 2013 visitation stood at 9.3 million, down from 9.68 million in 2012, though practically all of that drop might be attributed to the government shutdown, as October 2012 saw 1.14 million visit the park, while October 2013 recorded 847,616, a difference of almost 300,000.

Down steeply at Great Smoky Mountains, where there's a legal battle over the park's implementation of a backcountry user fee, was backcountry use. In 2012 the park counted 84,236 backcountry travelers, though last year that number dropped to 70,407.

How much of that drop can be attributed to the user fee is hard to say. In 2011, before the fee was instituted, there were 90,444 backcountry users at Great Smoky, though in 2010 the tally was 79,480. What contributed to the nearly 11,000-user jump? Was the weather better in 2011 than 2010? Were there counter errors in 2011?

You can explore all the 2013 visitation data at this site.