Debris Flow — Douglas, Washington

2013-08-10 · near Waterville, Douglas, Washington

Event narrative

Highway 2 at Pine Canyon was closed due to mud and debris covering the roadway for a period of time. The road was covered in six to eight inches of debris. The water dug three to four foot trenches within the drainage. The Douglas RAWS reported six tenths of rainfall in an one hour period.

Wider weather episode

Moist, southerly flow ahead of an area of low pressure trickling northward along the Oregon Coast created a moist, unstable environment over Central Washington. Shortwaves ejecting from the shortwave trough supplied the necessary lift to initiate numerous strong thunderstorms across the East Slopes of the Cascades and portions of the Western Columbia Basin. These storms developed during the evening and overnight hours of August 9th and persisted well into the morning hours of August 10th. Storms dissipated around midday then afternoon heating and a second shortwave triggered another round of strong storms during the afternoon and evening hours of the 10th. The main threat with these storms was high rain intensity and flash flooding, however one line of storms also delivered damaging winds.

View location on OpenStreetMap → (47.6507, -120.1520)

Source: NOAA Storm Events Database, event_id 471826. Narrative written by the NWS forecast office that issued the report.