patty app brown live in the newsroom with more on that story. patty app?va flow on hawaii's big island began in june. it has been slowly advancing and now threatening the largest town a half mile from the town's main street, now closed. and dozens of residents have been placed on alert, told to prepare for a possible evacuation at any time. the red cross is opening a shelter. the nearest home is at least 300 yards from the floe front, but it has already passed through a cemetery, covering grave sites. the floe stems from the kilauea vol cane know since 1983, most lava from its eruptions has flowed south. the past two years it has flowed northeast. its speed varies but authority says it has gotten faster lately. it's currently moving a rate of 15 to 20 yards per hour and has advanced more than 250 yards since saturday. meanwhile, the hawaiian volcano observatory says methane explosions have been going off. it happens when decomposing vegetation causes methane gas to accumulate in neekts can ignite. tense times there, john. >> crazy to watch that stuff movin