The hottest and fastest-moving lava of Kilauea volcano's latest eruption spread across new parts of the Big Island Wednesday, forcing officials to order evacuations in two coastal neighborhoods over fears that the rapidly advancing flows could cut off dwindling escape routes.

Overnight, the lava was moving fast enough to cover about six football fields an hour, according to US Geological Survey scientist Wendy Stovall.

"Hawaii County Civil Defense decided to evacuate all of lower Puna to ensure that people would be able to get out", Stovall said.

Lava gushed across and then along a roadway that leads from the commercial center of Pahoa toward smaller towns and rural farmlands to the east.

About two dozen recent fissures in that area have created towering lava fountains and bone-rattling explosions throughout the eruption.

The lava that is currently coming to the surface is the hottest and most fluid to date.