left. the guard standing by to provide security. abc s rob marciano is there. reporter: slow torture. that s what residents are calling the engulfing flow of lava. it s reshaping this island yard by yard as it makes its march toward pahoa. watch as the lava surrounds this telephone pole. fingers of lava just 100 feet from the nearest house. only one structure burned so far. once it crosses the road it will cut this town in half. the national guard called up to help manage this slow-moving disaster. fires and burning lava taking out all vegetation in its path. look at that. trees coming down as the lava encroaches on the outskirts of the flow. the lava burning the trees from the roots up. as the lava moves over the land you can hear the explosions from methane gas igniting. officials are monitoring the air