 -- A river of molten lava has oozed into a small Hawaiian town, covering the yard of two houses closest to the volcano, Hawaii County officials reported today.

The lava flow has been edging its way towards Pahoa on Hawaii's Big Island for weeks with authorities and residents powerless to halt or divert it.

"You can only imagine the frustration as well as... despair they're going through," Hawaii County Civil Defense Director Darryl Oliveira said of residents fleeing their homes.

The final number of Kilauea residents affected has not been released, but it is expected to be dozens. Officials said this afternoon that there are 40 to 50 houses in the path of the lava.

The lava is advancing at about 10 to 15 yards per hour, making it far slower than one might expect from a Hollywood version of the nightmare scenario, but it is moving at a steady pace. The Associated Press reports that the lava advanced about 275 yards from Sunday morning to Monday morning.

At other times, the lava slowed to about two yards per hour or sped up to about 20 yards per hour, depending on topography, said Janet Babb, a spokeswoman for the Hawaiian Volcano Observatory.

One major road has been closed to everyone except residents. Teams of scientists are among the few allowed close to the flow so that they can provide reports from the burning front line.

The lava is blisteringly hot, burying streets and covering trees. Residents in the scenic town of Pahoa were forced to flee, powerless to stop the river of lava.

"We don't know what we're going to do," resident Theresa Zendejas said. "It's really scary."

The lava has been spewing from the Kilauea volcano since it erupted in June. The lava flow has traveled 12 miles since then, at times speeding up erratically and recently fanning out to cover more ground.

Officials say there is no way to stop the lava, but they're working to protect power poles from burning and to create detours in case the main road is affected, which would cut off access for thousands of people. Hawaii officials are making arrangements for those living in the lava's path.

Beyond being buried by dozens of feet of hardened black rock, structures could also catch fire by being near the 2,000-degree lava.

Kilauea is the one of the world's most active volcanoes and has been erupting continuously since 1983. Lava flows have destroyed nearby homes in the past, including about 200 homes in the 1990s.

The Associated Press contributed to this report.