Residents in Washington state were preparing for possible flooding as “atmospheric rivers” once again threatened parts of the Northwest, which saw heavy damage from extreme weather earlier this month.

People in the small communities of Sumas and Everson in northwest Washington were asked to voluntarily evacuate Saturday night, The Bellingham Herald reported. Both towns near the Canadian border saw extreme flooding from the previous storm.

An emergency alert said road closures in the area could start early Sunday morning.

Flood watches have been issued for much of western and north-central Washington for the weekend, and the National Weather Service warned that flooding was possible through Sunday.

Heavy rains and rising rivers were also expected over the weekend in the Cascade mountains in the center of the state and the Olympic mountains near the coast.

“We are expecting rivers to rise, and possible flooding in some locations by early tomorrow morning,” Gary Schneider, a meteorologist at the National Weather Service’s Seattle office, said Saturday morning. “Right now, there’s no river flooding going on.”

Schneider said that if flooding were to occur, it would likely happen Saturday night or Sunday morning.

Forecasters say an atmospheric river — a huge plume of moisture extending over the Pacific and into the Northwest — could bring up to 3 inches (7.6 centimeters) of rain in some areas hit by the recent flooding.

The state is still assessing millions of dollars in damage from the last storm, also blamed on an atmospheric river.

In northwest Washington’s Whatcom County, officials said damage costs could reach as high as $50 million.

The last floods closed the U.S.-Canada border in Sumas and three bridges in Bellingham, with landslides blocking Interstate 5 south of Bellingham.

This weekend’s atmospheric river event should not be as “severe” as the one earlier this month, Schneider said.

“It’s still going to be a pretty decent rain event, but (the flooding earlier this month) was kind of an historic event. So we’re not expecting a repeat of that,” Schneider said.

Meteorologists predict that rain will taper off on Sunday and that Monday should be relatively dry.