NWS Flood Level Changes for White River

Unsettled Weather Continuing over the Western and Eastern U.S. into Mid Week

Two storm systems, one over the Desert Southwest, and one over the Ohio Valley, will continue to bring unsettled weather and cooler temperatures into the middle of the week. Moderate to heavy rainfall, along with the potential for flash flooding, is forecast from the Ohio Valley to the East Coast. Moderate to locally heavy rainfall is expected over the Northern Rockies, Great Basin and Southwest. Read More >

Public Information Statement National Weather Service Seattle WA 945 AM PDT Fri Nov 1 2019 ...Notification regarding a change in the Flood Warning levels for the White River... The National Weather Service has adjusted the flood warning levels for the river forecast points on the White River, effective today, November 1, 2019. The flood warning level, called flood flow or flood stage, is the river level at which a flood warning is issued by the National Weather Service to warn of flooding impacts. Flood mitigation efforts by local agencies have improved the carrying capacity of the lower White River such that flood impacts for the White River at R St. Bridge gage (WRAW1) in the vicinity of the cities of Auburn, Pacific, and Sumner are no longer an issue at the current flood flow of 5,500 CFS. High river flows in recent years reached 7000 CFS multiple times without causing flooding. In addition, LIDAR of the channel and subsequent flood inundation modeling supports a higher flood level. For the river forecast point White River Outflow from Mud Mountain Dam (MMRW1), the flood flow was 10,000 CFS back in 2009. When flooding first started to occur around the City of Pacific with river flows below 8,000 CFS, the MMRW1 flood level was lowered 8,000 CFS to account for that. Once the river forecast point at R St. Bridge was established to specifically cover the lower White River, the artificially low flood level for MMRW1 was no longer needed. The following new flood levels on the White River have been coordinated with the Emergency Management Divisions and Public Works Departments of Pierce and King Counties, and the above cities. The moderate and major flood flows remain the same at both locations at this time. Here are the new and old flood flows: River Gage New Flow Old Flow White River at R Street Flood Flow/Minor Flood 6,500 CFS 5,500 CFS White River below Mud Mountain Dam Flood Flow/Minor Flood 9,000 CFS 8,000 CFS If you would like more information about the National Weather Service hydrologic services in the Seattle area, please contact Brent Bower, Senior Service Hydrologist, at 206-526-6095.