Officials were going door-to door to about 50 homes to keep residents informed of the lava's movement, said Darryl Oliveira, the director of civil defense for Hawaii County. The county will issue a mandatory evacuation order if the flow begins advancing at such a rate that it would be difficult for people to move out of the way with little notice, Oliveira said. Burning asphalt was generating some smoke, but Oliveira said the wind dispersed the fumes over unpopulated areas and it didn't pose a health risk at the moment. Sporadic suspensions in the lava's movement gave emergency crews time to work on building alternate routes to town in the event the flow covers the main road and highway.