It's been a hot, dry year in Portland. But rain is coming.

According the National Weather Service of Portland, an "atmospheric river" of moisture is on its way to the Pacific Northwest.

Heavy rain is predicted to dump over the city tonight and tomorrow, while wind gusts are expect to reach 45 mph. The downpour will likely cause flooding on Portland roads and could also lead to landslides.

The National Weather Service advises residents in the Portland area to be on alert for debris flows today through Wednesday.

"A debris flow moves faster than a person can run," the advisory cautions. "People, structures and roads located below steep slopes in canyons and near the mouths of canyons may be at serious risk."

NWS says people should track flood watch notices, travel with caution as roadway embankments may fail and evacuate immediately if they see or hear "trees cracking or boulders knocking together."

Data provided to WW's news parter KATU News show a spike in Johnson Creek and Tualatin River water levels, which could also cause minor flooding.

The NWS and Portland Bureau of Transportation are advising people to clear storm drains and gutters today and to prepare for long and potentially dangerous commutes tomorrow morning.

Those with coastal travel plans may also want to reconsider.

NWS has issued surf advisories along Oregon and California coast, warning that breaking waves could reach heights of 25 to 40 feet.

"High surf warnings were issued by the NWS from Point Conception, California, to the coast of southwest Washington," the agency notes, "highlighting an especially heightened threat to life and property within the surf zone."