According to the National Weather Service, new flooding is possible Friday through Saturday throughout Western Washington. Heavy rain overnight and another round of rain Wednesday night will keep rivers at elevated levels and the ground very wet. A heavy rain event is forecast for Friday through Saturday. One to three inches are expected in the lowlands with four to seven inches in the mountains. Snow levels will be rising above 6000 feet. This amount of rain could produce flooding on many rivers, streams, and urban areas. At this time, there is some possibility of moderate or even higher flooding.
The landslide threat will also be increasing. Repeated periods of rainfall over the last several weeks has increased soil moisture to high levels across western Washington. Moderate rainfall of up to an inch and a half on Wednesday is expected. This amount of rain will put extra pressure on soil instability, leading to an increased threat of landslides being triggered. This will mostly affect the coast and foothills.
A number of landslides have already been reported in various locations in western Washington over the last week during or right after the rainstorms that have occurred. More landslides are