The latest ferocious storm system to hit the Pacific Northwest triggered fresh evacuation orders and at least one mudslide in flood-ravaged British Columbia, Canada, late Sunday.

Threat level: Flood sirens sounded in Washington state as the Nooksack River overflowed. Henry Braun, mayor of Abbotsford, B.C., told reporters the water flow was headed toward the Canadian border city later Sunday. "There's nothing to stop it," he said.

Abbotsford Fire trucks pumping water into the tiger dams.
Crews are working to set them up tonight on #BChwy1 in #Abbotsford to hold back Sumas River floodwaters. Working in collaboration with the Canadian military, Shxwowhamel Ventures, @AbbyPoliceDept @BCRCMP. #BCstorm pic.twitter.com/LqkAB2mz9m

— BC Transportation (@TranBC) November 29, 2021

Meanwhile, periods of heavy rain on top of already saturated soils were expected to lead to "additional flooding and continued threats of landslides across western Washington," the National Weather Service warned.

State of play: Abbotsford has been under evacuation alert since an atmospheric river event first brought record levels of rainfall, flooding and mudslides to the Pacific Northwest this month. Braun said water levels in the city had exceeded 17 inches so far.

• Fresh evacuation orders and alerts were issued for the region on Sunday amid the latest atmospheric river — including in one area of Abbotsford that was hit by a mudslide amid the evening's heavy rains.
• Parts of Washington were also under flood watches and warnings overnight.

What to watch: The latest atmospheric river, or plume of moisture, was slowly weakening overnight, but the National Weather Service said Monday morning it was expected to produce heavy rains over parts of the Pacific Northwest through Tuesday.

• "Rainfall amounts in the U.S. will be highest over areas that border British Columbia such as the northern Cascades and Olympic mountains due to orographic enhancement," as precipitation may increase in intensity, per the NWS.
• "Only a few inches of rain are expected to accumulate by the time that the AR event ends on Tuesday night."

The bottom line: Extreme weather events are the clearest way we're feeling climate change in our daily lives, Axios' Andrew Freedman and Kia Kokalitcheva write.

Somebody else pointed this out today--it does look like Seatac has had the wettest fall (well, Sept thru Nov) on record. Here's the top ten: pic.twitter.com/rzReLWRTDE

— NWS Seattle (@NWSSeattle) November 29, 2021

Go deeper: Extreme weather outruns the world

Editor's note: This article has been updated with more details on the storm's impact on Canada and further context.