A slow-moving tongue of lava is within a quarter-mile of the boundary of Hawaii Volcanoes National Park.

Park officials say the mile-wide swath of lava from an October breach of a lava tube broke away from the main flow and is crawling toward the park.

It could enter the park this week. Volcanologists walked along the perimeter of the flow Monday to pinpoint its location using handheld global positioning system devices.

No lava has reached national park land since last year.

Park and county officials are in discussions about how to handle public access to the lava flow. It's possible to see it up close, but only after a six-mile trek over dangerous and unmarked terrain.