Kilauea Update: The lava flow burns vegetation as it approaches a property boundary in a U.S. Geological Survey (USGS) image taken near the village of Pahoa, Hawaii, October 28, 2014. A slow-moving river of molten lava from an erupting volcano flowed through a residential property on Hawaii's Big Island, threatening dozens more homes and businesses, authorities said. The lava has been heading toward the town of Pahoa for weeks, with recent speeds averaging around 15 yards (13.7 meters) an hour. Picture taken October 28, 2014. Reuters/U.S. Geological Survey/Handout

The massive molten lava flow from Hawaii's Kilauea volcano has threatened homes and businesses on Hawaii’s Big Island and is now complicating tourism in the area. With no end to the flow in sight, authorities, volcano tour companies and locals said they aren't sure how bad it will get.

That's no small matter in Hawaii, where tourism represents the state's largest source of private capital. Volcanoes National Park, of which Kilauea is the main feature, is the No. 1 visitor attraction in the state, according to tourism officials. Over 8.2 million people visited Hawaii last year and spent $14.5 billion. With a handful of record-breaking months already in the books this year, 2014 looks to be another profitable year.

Deborah Ward, of the Division of Forestry and Wildlife, said her agency has had trouble with tour guides bringing guests to see the flow. She said tourists looking to see the lava flow are putting themselves at risk. “Lava flows are inherently dangerous,” she said. “There are fissures, cracks, methane explosions, and fire. Hot lava can shoot off rocks like bullets.”

Volcano tourism can be a major revenue generator for local economies. Iceland has seen a boom in visitors looking to check out an active volcano after the Eyjafjallajokul eruption in 2010 piqued international interest. The Democratic Republic of Congo, too, saw a boost in tourism dollars from people coming to see Mount Nyamulagira in Virunga National Park when it steadily spewed lava in 2011. Kilauea, however, is easily one of the top volcano tourism destinations in the world. It’s one of the most, if not the most active volcano in the world, and Hawaii has cashed in for years.

Kilauea's lava flow is already 14 miles long -- twice that of its normal flow -- and doesn’t show signs of stopping, according to the United States Geological Survey’s Hawaiian Volcano Observatory. If it makes it to the sea, it will likely cut through a handful of communities in the way, a serious threat. After the lava flow started to grow, some locals considered moving elsewhere on the island, while others already have.

But to some tourists, the lure of seeing lava in live action is irresistible. “If it comes into a more public area, it will bring us more business,” Mark DeVita, owner of Hawaii Volcano Tours, said. “I can tell people that yes, I can take you to a place where we can see [lava]."

On the other hand, DeVita said, it could entirely shut down the area and make tours even harder to conduct. If the lava flow makes it to the ocean and doesn’t slow up, the Civil Defense Agency has an alternate travel plan that runs around Volcanoes National Park that would add 80 to 90 minutes to locals’ commute. That could kill the local economy that’s built on tourists coming to catch a bit of the Hawaiian countryside and on agriculture. Bed-and-breakfasts would have fewer guests, bars and restaurants fewer patrons.

Local authorities said the immediate priority is getting people out and safe. They are building new access roads to get supplies and people in and out. The flow is 260 yards away from Pahoa Village Road, the main road in the most vulnerable town as of 7 a.m. local time on Wednesday. At its slower rate of 5.5 yards per hour, the flow would cross Pahoa Village Road by Friday morning. The Civil Defense Agency has cut off a quarter-mile stretch of Pahoa Village Road where the lava is expected to cross.

Kilauea Volcano update: Construction crews prepare Pahoa Village Road as lava flow from Mt Kilauea approaches the village of Pahoa, Hawaii October 28, 2014. The menacing river of molten lava that bubbled over a road and overran a cemetery on its path toward a village on Hawaii's Big Island crossed onto a residential property on Tuesday where it threatened to consume its first home, officials said. Reuters/Marco Garcia
Kilauea volcano update: The lava flow from the Kilauea Volcano is seen nearing residential areas in a U.S. Geological Survey (USGS) image taken near the village of Pahoa, Hawaii, October 27, 2014. The flow, which first bubbled out of the continuously erupting Kilauea on June 27, came to a standstill in late September but resumed its trudge several weeks ago. It has moved about 275 yards since Sunday morning and is now 70 yards (64 meters) from the nearest home. Picture taken October 27, 2014. Reuters/U.S. Geological Survey/Handout

Before threatening Pahoa, the flow moved through Puna Forest Reserve, prompting authorities to close it, so most guides haven't been able to capitalize on the unprecedented event, but some guides have conducted semi-legal tours, DeVita said.

DeVita said there was a march organized by one of the larger tour operators to demand authorities allow them to run tours near the lava flows, but he didn’t attend and wasn't sure it would lead to any changes.

“This is a historic event and people want to see it and have access to it,” he said.

Ward said tourists should instead visit state-sanctioned viewing areas in Volcanoes National Park, which are cleared for safety -- although they can still be quite dangerous -- before checking out the unpredictable flow. People should respect and understand the needs of the communities now at danger, she added.

“The last thing people need is sightseers,” she said.