Flash Flood — Okanogan, Washington

2001-07-12 · near Oroville, Okanogan, Washington

Wider weather episode

Three to five inches of rain caused a significant 100+ year flash flood over the higher terrain of northeast Okanogan County on the evening of July 12. The weather pattern showed an upper level high pressure ridge over the western United States with monsoonal moisture extending northward into Washington. Early in the evening, a band of northward-moving thunderstorms developed over northeast Okanogan County which continued to re-generate on its southern flank for 2-3 hours. Excessive rainfall and flash flooding were the result. The worst flash flooding occurred along a stretch of the Oroville-Chesaw Road. Three separate drainages contributed to the event: an unnamed creek that flows from Fletcher Mountain, Dry Creek and Tonasket Creek. A "wall of mud" blasted across Oroville-Chesaw Road where the unnamed creek crosses under the road (one mile east of its intersection with Molson Road), washing a van into the raging creek around 915 PM PDT. A 56-year old grandmother in the van pushed her granddaughter out in time for the granddaughter to escape injury. The grandmother could not escape the van and was presumably washed away inside it. The grandmother is missing and assumed dead (direct). Her body was never found in the deep mud. Significant damage occurred in this rural part of Okanogan County. Eden Valley Road was completely washed out. A bridge along Dry Gulch Road was washed out. Damage to other county roads in the vicinity was extensive. At the Eden Valley Guest Ranch, fences and other farm implements were washed away. A grain bin was washed 30 feet away from its foundation. Water rose high enough to cause damage to parked vehicles. Mud filled another grain bin, a basement, garage, shop and barn. Much of the damage in the area was not covered by flood insurance.

Source: NOAA Storm Events Database, event_id 5259482. Narrative written by the NWS forecast office that issued the report.