There is an increased threat of landslides for the lowlands from Snohomish to Jefferson Counties southward. Areas where there is melting snow and rainfall is saturating the soil. The landslide threat will increase through the week and expand northward to the Canadian border and upward in elevation into the foothills as warmer weather continues to move into the region.
Melting snow is very efficient at increasing soil moisture and is not well represented in the landslide indices such that the threat is higher than the indices suggest. Additional rain Thursday will put extra pressure on soil instability, leading to further increased threat of landslides.
Areas above around 1500 feet in elevation will see mostly snow and freezing temperatures and will not be affected.