The National Weather Service in Portland has issued a flood watch for the South Washington Coast and Willapa Hills through Tuesday evening.
Three to 5 inches of rain over the past 24 hours have resulted in area streams and rivers running at unusually high levels. An additional 1.5 to 2.5 inches of rain is expected to fall across the Willapa Hills Tuesday. A 2-4 hour window of heavier rain this afternoon could push some area rivers above flood stage. The Naselle River, and particularly the Willapa River, will be the most susceptible to reaching minor flood stage.
If minor flood stage is reached along the Willapa River, Heckard Road will become inundated. Portions of US 101 may also become inundated in the evening as high tide approaches.
If minor flood stage is reached along the Naselle River, historically, water surrounds some homes along the river, and a few low lying sections of Washington State Route 4 will become inundated.
Landslides and debris flows are possible during this flood event. People, structures and roads located below steep slopes, in canyons and near the mouths of canyons may be at serious risk from rapidly moving landslides.
In addition, a coastal flood advisory is in effect from 9 a.m. to noon Tuesday along low-lying areas of the South Washington Coast. Tidal overflow flooding is expected. The total tide will near 10.5 feet at 10 a.m.
Similar conditions in the past have resulted in minor flooding in Raymond, on HWY 101 near South Bend, and/or minor erosion of HWY 105 near North Cove. Inland run-ups are possible on beach approach routes.