The molten material is flowing seven miles from the source to the sea, cascading into the water for the first time since last December.
Vulcanologists at the U.S. Geological Survey say the lava is creating a hard delta of debris when it makes contact with the Pacific.
But they warn that the expanded territory it is creating for the Big Island is unstable and can collapse at any time without warning.
Officials say no homes or commercial properties are threatened by the lava flow.
Photo: Leigh Hilbert