MISSOULA, Mont. — The Clark Fork River near Missoula began receding Saturday after it crested at the highest level in more than a century and swept trees, trailers, and other debris downstream. But forecasters said residents are not out of danger yet.

The National Weather Service said the river will drop only slightly before rising to an even higher level next week, as warmer temperatures continue to melt mountain snow. Heavy rains in recent days have compounded the deluge caused primarily by melting snow.

Meteorologist Ryan Leach said Saturday that the river will be at flood stage for weeks to come.

Authorities have ordered the evacuation of about 65 homes, and more than 800 others are under an evacuation warning.

The river crested late Friday at 13.82 feet, its highest level since 1908, and the second-highest level ever recorded.

The river is forecast to start rising again Tuesday and reach 14 feet next week.

Many residents under evacuation orders refused to leave last week.

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 trailer home that was pushed off its foundation and broke apart in the floodwaters, authorities said.

‘‘It’s a great public safety concern for us,’’ said Mel Holtz, a firefighter and spokesman for the flood response effort.

On Thursday, officials rescued one man by using a boat to reach a camp for transients on a partly submerged island on the Clark Fork. Firefighters at the river’s edge found him hanging onto a tree.

In Washington State on Saturday, Governor Jay Inslee proclaimed a state of emergency for counties in the eastern part of the state that are experiencing severe flooding.

Flooding is affecting communities in Ferry, Okanogan, and Pend Oreille counties and could get worse next week, forecasters said.

The proclamation covers those three counties as well the 17 other Eastern Washington counties facing an increased threat of flooding over the next seven days.

‘‘Flooding caused by recent rains and snow melt has fouled water and sewage treatment facilities, threatened state highways and local roads, and caused some people to leave their homes,’’ Inslee said.

‘‘Continued higher temperatures are predicted to increase snow melt and cause additional flooding as rivers and streams continue to rise to record or near record levels,’’ he said.

State agencies and local jurisdictions are coordinating resources to address the effects of the flooding, and the governor’s proclamation directs state agencies to implement appropriate response activities.

The State Emergency Operations Center at the Washington Military Department’s Camp Murray was activated Saturday to monitor local efforts and coordinate resources to help local officials respond.