The threat of explosive eruptions from Kīlauea has prompted a decision to close most of Hawai'i Volcanoes National Park for the immediate future/USGS

As Kīlauea Volcano becomes more active and poses an explosive threat that could toss blocks of rock into the air, Hawai'i Volcanoes National Park officials are closing most of the park for the immediate future.

All areas of the park but the Kahuku Unit, which will remain open during normal hours Fridays through Sundays, will close Friday until further notice due to the possibility of an explosive steam event and ash fall at the volcano's summit.

On Wednesday the Hawaii Volcano Observatory issued a statement that the volcano could produce explosive eruptions that eject ballistic blocks 6 feet wide and weighing a ton or more.

"The steady lowering of the lava lake in 'Overlook crater' within Halemaʻumaʻu at the summit of Kīlauea Volcano has raised the potential for explosive eruptions in the coming weeks. If the lava column drops to the level of groundwater beneath Kīlauea Caldera, influx of water into the conduit could cause steam-driven explosions," the observatory said. "Debris expelled during such explosions could impact the area surrounding Halemaʻumaʻu and the Kīlauea summit. At this time, we cannot say with certainty that explosive activity will occur, how large the explosions could be, or how long such explosive activity could continue."