Officials in Indonesia say more than 170 people were killed in a flood that hit a tourist resort on Sumatra Island, and they expect the number to rise. Local officials say illegal logging contributed to the disaster.

For a second day, rescuers worked their way through the debris of the town of Bukit Lawang looking for survivors, but they mostly found bodies.

A wall of water hit the tourist town early Monday, when most people were asleep in the flimsy houses and hotels that line the River Boharok.

The town sits in a narrow valley between steep walls, which concentrated the power of the water. Television footage shows most of the town has been destroyed.

Bukit Lawang is popular among tourists visiting the nearby Gunung Leuser National Park, with its orangutan rescue center. At least five of the dead were tourists from Europe and Asia.

Local officials say the town should have been protected from flooding. The headwaters of the River Boharok are inside the national park, where logging is banned. But authorities say illegal logging has stripped the highlands of cover, amplifying the floods that are always part of the wet season this time of year.

Some attempts have been made to curb the damage done by illegal timber operations, but to little effect. Powerful Indonesian interest groups, including the army and influential politicians, are involved in the trade, and attempts to restrict demand for rare hardwoods in developed countries are not having a lasting effect.

Environmentalists warn that more disasters like Monday's are inevitable.