The Stilliguamish suddenly came to a dead end after a massive landslide Thursday. It completely blocked The North Fork. Now the river is carving its own path around the landslide, into back yards and neighborhoods.
The main concern is water is building up behind the slide, threatening homes up river.
"If the water comes up and the debris comes down, it's going to dam up things here. That will make the water keep coming up and we'll have to move," said homeowner, Larry Forsman.
That's exactly what the county is telling people to prepare for.
"We are asking them to be ready to evacuate and be ready to move quickly because we do not know what's going to happen," said Owen Carter, Snohomish County Engineer.
At a community meeting, residents learned the Army Corp of Engineers will try to cut a channel through the debris of the landslide.
"How fast we can do this and how effective it will be, we don't know," one engineer admitted to the crowd.
In the meantime, volunteers kept filling sand bags to protect homes. But if the forecasted rains arrive, county engineers say the plugged river could increase in flow by five times.
"We are going to prepare for it," said home owner Ron Thompson, "We got a trailer and we're going fill it up. That's the best thing we can do."
The land that gave way has been a problem since the 1940's. As the river cut under it, the potential size of a landslide kept getting bigger, until our recent heavy rains brought it down.
"It has grown quite a bit -- it's probably close to 50 acres," said Noel Wolff, a Geologist with the Department of Natural Resources.
Response teams are doing all they can to keep the river from flooding homes, but nature is in charge.
As one home owner watched the water inch closer, he simply said "We will just have to wait and see."