MISSOULA, Mont. (AP) - Montana rescuers pulled a man from raging floodwaters and authorities warned of dangerous debris being swept downstream as water levels continued rising Friday in rivers and streams across the western half of the state.

The Clark Fork River in Missoula was expected to crest Saturday at its highest level in 100 years, according to the National Weather Service.

Floodwaters already have inundated some houses and trailer homes in a low-lying neighborhood in Montana's second-largest city.

Many residents of the more than 65 houses under evacuation orders refused to leave. That put both residents and emergency personnel in danger as debris surged downstream, including sheds, a propane tank and the remains of at least one broken apart trailer home, authorities said.

"It's a great public safety concern for us," said Mel Holtz, a firefighter and spokesman for the flood response effort. "Obviously it's a very difficult time for people to leave, but we have concerns over utilities in that area because the electricity is still on and there's a lot of debris in the water."

The rescued man was using a small raft to reach a camp for transients on a partially submerged island on the Clark Fork Thursday night.

Firefighters at the river's edge noticed him hanging onto a tree and still in the raft, Holtz said. Rescuers used a boat to pull him to safety.

No injuries had been reported as of Friday morning, Holtz said. Occupants of about 800 Missoula houses were under warning that they may have to evacuate if conditions deteriorate.

Water also was pushing into residential areas downstream along the Clark Fork in the town of Frenchtown, where occupants of two houses were ordered to evacuate.

The river is expected to say at major flood level for at least a week, giving plenty of time for it to do more damage, said National Weather Service meteorologist Alex Lukinbeal.

Personnel from the U.S. Army Corps of Engineers were monitoring area levees but they were not expected to be topped, Holtz said.

Floodwaters also threatened homes along the Blackfoot River near Lincoln and portions of Lewis and Clark, Jefferson and Broadwater counties.

In central Montana, the Musselshell River near the small town of Shawmut in Wheatland County was forecast to reach major flood stage Saturday. The county sheriff's office advised people not to drive through flooded areas.

Rain was in the forecast Friday afternoon with showers possible through the weekend across much of the state. Most of the floodwater is coming from the rapidly melting snowpack in the mountains.

Copyright 2018 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.