Wow. My mom had a house in Rio Oso, right on the Bear River.
Not good.
Seeing as you are in Seattle(?), recall the Oso Landslide that we had in Western Washington a few years ago (you mentioned Rio Oso River). Mother nature doesn’t give a crap about us humans - whether the killed number in the 20’s, 200’s or 2,000’s. Prayers for those caught up in this real-life nightmare disaster that could be pulled straight from the movies.
Help the emergency folks coordinate traffic flows, give them extra time, help people make rational decisions. Calm those separated from their loved ones.
Aftermath of the Oso Landslide:
https://www.youtube.com/watch?v=RuhXEjRl1XU
Prayers for your mom