Yellowstone National Park, which attracted national attention in 1988 when wildfires burned nearly half the 2.2-million-acre park that hot and dry summer, so far has managed to avoid any fires this summer.

Fire danger in the park, though, is "very high," says Superintendent Dan Wenk.

"We’ve currently had no fires in the park. Hopefully I’ll be able to say that for a while longer," he said Thursday.

To guard against human-caused fires, Yellowstone officials have implemented the following restrictions:

• Lighting, building, maintaining, attending, or using a fire of any kind is prohibited in the backcountry including established campsites. Campfires are only allowed in an established fire grate at front country campgrounds, picnic areas, or housing areas. Use of portable stoves and lanterns using gas, jellied petroleum or pressurized liquid fuel, or use of a fully enclosed sheepherder type stove with a spark arrester screen is permitted.

• Smoking is prohibited in the backcountry and on all trails. It is permissible in the front country only in an enclosed vehicle or while stopped in an area at least three feet in diameter that is barren or cleared of all flammable materials.

• All are reminded that the discharge of fireworks in Yellowstone National Park is prohibited and subject to penalties including fines and jail time.

“We're doing everything we can do to limit to our ability to prevent man-caused fires in the park," Superintendent Wenk said. "Certainly, we can’t limit the thunderstorms that come through."

While the park has benefited from a "pretty wet spring," he said, in recent weeks Yellowstone has experienced "pretty high temperatures and pretty strong winds and things have dried out substantially.”

The bottom line, said the superintendent: “We're vulnerable.”