Lava is cascading off the steep slope of the Pulama pali and is visible from Kalapana for the first time since January of 2013.

To accommodate people who want to see the lava, Hawaii County is opening a parking area and will open a 3-mile stretch of the new emergency access road to the Hawaii Volcanoes National Park, starting Thursday night from 3 p.m. to 9 p.m. daily.

People will only be allowed to walk on the road. Vehicles, except for emergency vehicles and local residents, must park their cars and walk on the gravel portion of the road, Hawaii County Civil Defense said in a news release.

Security guards will be posted at the end of the paved Highway 130.

The emergency access road was cut through old lava flows at a cost of about $10 million when Pahoa was threatened by a lava flow in 2014 to 2015. The gravel road connects Highway 130 with Chain of Craters road in the national park.

The Hawaiian Volcano Observatory released new photos and a video of the lava at the top of the pali on Tuesday.

Jeff Sutton, the acting scientist in charge at the Hawaiian Volcano Observatory, said the lava advanced about 1,500 feet today as it makes its way to the bottom of the pali. It had been advancing at a rate of about 300 feet a day until it reached the pali.

The flow had been a slower-moving pahoehoe flow until Tuesday. It sped up and changed to a rocky and faster-moving aa flow as it moved over the steep terrain of the pali.

Once it reaches the bottom of the pali, it will be about 2 miles from the emergency access road and the ocean.

Sutton expects the forward progress of the flow to slow when it reaches the flat, coastal plain before the ocean.

He said the lava appears to be headed for a depression and will likely widen and fill the depression before it can continue moving toward the sea.

The lava is within the national park boundary.

Jessica Ferracane, a spokeswoman for the Hawaii Volcanoes National Park, said park visitors can see the glow from the lava from scenic lookouts along Chain of Craters Road.

Visitors can hike to the flow, but Ferracane cautioned the hike is a “grueling 11-mile roundtrip hike over hardened lava … definitely not for everyone and hikers must be prepared.”

Sutton said there is also a danger of methane gas explosions for those getting close to the lava.

He said the lava is going through forest and pockets of gas from the burning vegetation can build up and explode long after the lava has cooled.

Ferracane said the park service may set up a lava viewing area if the flow becomes visible from safe vantage points along the coastal plain. But the emergency access route within the park boundaries will remain closed to preserve its use in case of emergencies.

Hawaii County Civil Defense said people who want to walk to the border of the national park should also be prepared for the six-mile roundtrip hike with proper footwear, sun screen, warm clothing and water.

The current lava flow began on May 24 and has advanced about 4 miles from the east slope of Puu Oo vent.

If the lava flow continues and reaches the ocean, it will be the first time since the 2011 Peace Day flow, which also went over the pali near the now-abandoned Royal Gardens subdivision.

At Halemaumau at the Kilauea summit, lava spattering in a pond in the crater was visible Monday night to visitors to the Jagger Museum overlook.

The lava lake level was about 80 feet below the crater floor, but has since dropped to about 110 feet below the floor of Halemaumau, out of sight of tourists.