‘Need to be prepared’

Methane gas erupting through cracks on Kahukai Street in the Leilani Estates neighborhood of Pahoa burns blue Wednesday night. When lava buries plants and shrubs, methane gas is produced as a byproduct of burning vegetation. It can seep into subsurface voids and explode when heated, emerging from cracks in the ground several feet away from the lava. (U.S. Geological Survey/via AP)

Right: Marines conduct a helo-cast from a CH-53D Sea Stallion off the coast of Hawaii. (US MARINE CORPS

Left: The active fissure complex in Kilauea Volcano’s lower East Rift Zone near Pahoa, Hawaii produces methane Wednesday as hot lava buries and burns plants and trees. Scientists say the methane can seep through cracks several feet away from the lava. (U.S. Geological Survey/via AP)

HILO — With one highway severed and another one threatened, officials continue to be frank about the possibility of lava flows isolating residents in lower Puna.