Monica Samayoa

Atmospheric rivers are essentially a jet stream or river of warm moisture in the sky, bringing in more rain than normal storms.

That could lead to major flooding or landslides in areas not prepared to receive a burst of heavy rain.

State climatologist of Oregon Larry O'Neill says the region gets about 10 to 15 of these kinds of events annually, and climate change can make it worse.

So far, several flood advisories are in place as the region expects more rain to fall through Saturday.

For NPR News, I'm Monica Samayoa in Portland.

Atmospheric rivers are essentially a jet stream or river of warm moisture in the sky bringing in more rain than normal storms.

That could lead to major flooding or landslides in areas not prepared to receive a burst of heavy rain.

State climatologist of Oregon Larry O'Neill says the region gets about 10 to 15 of these kinds of events annually, and climate change can make it worse.

So far, several flood advisories are in place as the region expects more rain to fall through Saturday.

For NPR News, I'm Monica Samayoa in Portland.