Issued by the King County Flood Control District on April 11, 2025
Flood Event Summary
On Thursday, March 27th, the U.S. Army Corps of Engineers (USACE) informed King County, Pierce County, and cities along the White River of a planned release of water from the Mud Mountain Dam. The Mud Mountain Dam is a flood control dam operated and maintained by the USACE which protects the lower White and Puyallup River valleys from flooding by holding back water from heavy rains and melting snow in its reservoir. Controlled water releases from Mud Mountain Dam helps to ensure there’s enough room in the reservoir behind the dam to store spring runoff flows, when melting snowpack and additional rainfall can lead to sharp rises in water levels within the White River’s upper watershed.
On Sunday, March 30th, the USACE told King County staff that outflow increases would start Monday, March 31st, rising slowly to 4,400 cubic feet per second (cfs), and that they were targeting a release of 5,000 cfs on Tuesday, April 1st. Flood Phase 1 for the White River is at 4,000 cfs, based on the flow gauge at the Mud Mountain Dam. Flood Phase 2 triggers at 5,000 cfs.
At 4:00 p.m. on Monday, March 31st, the Mud Mountain Dam gauge registered 4,350 cfs, triggering a Flood Phase 1 alert. By 9:30 a.m. on Tuesday, April 1st, the controlled release of water from the Mud Mountain Dam by the USACE reached a flow of 5,180 cfs just below the dam. This exceeded the 5,000 cfs threshold for a Flood Phase 2 alert. The King County Flood Warning Center opened at 9:40 a.m. to monitor the rising water levels from the controlled release.
The King County Flood Warning Center closed at 5:15 p.m. on April 1st after monitoring minor flood levels on the White River for approximately seven hours. Even though the Flood Warning Center closed, King County continued coordination with the USACE throughout the week and monitored weather data in case conditions changed. The White River remained at Flood Phase 2 levels until April 4th while the USACE continued its controlled water release from the dam. By 8:00 p.m. on Friday, April 4th, water levels dropped below the 4,000 cfs Flood Phase 1 level, and by the morning of Sunday, April 6th, the flow in the White River below the dam returned to regular conditions around 1,500 cfs.
An interesting factoid: This is the fourth time in 2025 the King County Flood Warning Center has been activated. The last time the Flood Warning Center opened was on March 27, 2025.
Response Overview
This section lists some of the actions taken by the King County Flood Control District and its governmental partners. It is not intended to be an all-inclusive list of governmental actions taken during this flood event.
- April 1: King County opened the Flood Warning Center at 9:40 a.m. to monitor flooding along the White River.
- April 1: The King County Flood Warning Center closed at 5:15 p.m. in coordination with the USACE controlled water release from the Mud Mountain Dam.
Communications Summary
This section lists some of the communications provided by the King County Flood Control District and its governmental partners. It is not intended to be an all-inclusive list of governmental communications provided during this flood event.
- March 31 at 4:53 p.m.: Flood Warning System email sent from King County about the White River indicating phase direction is moving upward, and Phase 1 flow is 4,350 cfs based on the gauge below the Mud Mountain Dam.
- April 1 at 9:54 a.m.: Flood Warning System email sent from King County about the White River indicating phase direction is moving upward, and Phase 2 flow is 5,180 cfs based on the gauge below the Mud Mountain Dam.
- April 1 at 10:04 a.m.: Flood Alert System phone call and email sent by King County indicating the White River has reached Flood Phase 2 and the City of Pacific may have overbank flooding and the Red Creek area may have overtopped roads and high water.
- April 1 at 10:08 a.m.: King County provided an email update to the King County Flood Control District indicating the Flood Warning Center was activated at 9:40 a.m. and a news release was going to be sent out.
- April 1 at 10:15 a.m.: King County provided an email update to area media outlets.
- April 1 at 10:21 a.m.: Steven Schauer, Deputy Executive Director of the King County Flood Control District, provided an email update to the Board of Supervisors and an extended group of staff members. The Chair and Vice Chair were also contacted by text.
- April 1 at 10:41 a.m.: King County Flood Control District posted a flood update on Facebook, tagging the cities of Auburn and Pacific.
- April 1 at 10:44 a.m.: King County Flood Control District posted a flood update on X, tagging the cities of Auburn and Pacific.
- April 1 at 10:44 a.m.: King County Flood Control District posted a flood update on Bluesky.
- April 1 at 12:17 p.m.: King County provided an email update to the King County Flood Control District indicating the Flood Warning Center is expected to close later in the day.
- April 1 at 7:19 p.m.: King County provided an email update to the King County Flood Control District indicating the Flood Warning Center was closed at 5:15 p.m. and a news release was going to be sent out.
- April 1 at 7:20 p.m.: King County provided an email update to area media outlets.
- April 2 at 9:32 a.m.: Michelle Clark, Executive Director of the King County Flood Control District, provided an email update to the Board of Supervisors and an extended group of staff members. The Chair and Vice Chair were also contacted by text.
- April 2 at 5:27 p.m.: King County provided a final email update to the King County Flood Control District.
- April 4 at 1:52 p.m.: Flood Warning System email sent from King County about the White River indicating phase direction is moving upward, and Phase 2 flow is 5,520 cfs based on the gauge below the Mud Mountain Dam.
Infrastructure and Critical Facilities
This section assesses the impact of flooding on critical infrastructure such as roads, bridges, utilities, and public facilities, and it highlights past investments which may have mitigated the impact of this flood event. It is not intended to be an all-inclusive list of flooding impacts, nor does it highlight all past government investment in area flood mitigation infrastructure.
For Flood Phase 2 flooding on the White River, overbank flooding could occur in the City of Pacific near Government Canal and within Pacific City Park. High water could also occur along the temporary flood protection barriers lining the river through the City of Pacific. The Red Creek area may also have overtopped roads and high water.
The following images are associated with areas where river facilities exist. You can learn more about locations of river facilities, floodplains, and other important flood related information by using King County’s iMap.
A river facility refers to any man-made or engineered structure that interacts with a river system, with the purpose of influencing or controlling water flow, particularly to reduce flood risks. These include levees and revetments. A levee is a natural or artificial river embankment that prevents flooding, and a revetment is a passive structure that protects against erosion caused by river currents and high flows.
Pacific City Park Revetment on the right river bank of the White River
Countyline Levee Setback Project on the left river bank of the White River
A project was completed at this location in 2017.
A Street HESCO Barriers Project on the right river bank of the White River
A project was completed at this location in 2024.
Pacific Right Bank Flood Protection Project on the right river bank of the White River
A project is being designed at this location.
Union Pacific Levee on the left river bank of the White River
A-Street Trailer Court Revetment on the right river bank on the White River
Oravetz School Revetment on the left river bank on the White River
Roegner Park Revetment on the left river bank on the White River
R-Street DS Revetment on the left river bank on the White River
Segale-White Revetment on the right river bank on the White River
R-Street US Revetment on the right river bank on the White River
Stuck River Drive Revetment on the left river bank on the White River
Game Farm Wilderness Park Levee on the left river bank on the White River
Valley Wall Revetment on the right river bank on the White River
Lessons Learned
This section lists some of the lessons learned by the King County Flood Control District and its governmental partners. It is not intended to be an all-inclusive list of governmental lessons learned during this flood event.
- Flood forecasting and warning appeared to function as designed given there was no loss of life in King County during this flood event.
- Existing flood risk reduction infrastructure appeared to function as designed given flooding impacts were minimal.
- Media outreach and coverage appeared to function as intended to help keep the public properly informed and minimize public risks.
- Flooding, while minor, underscores the policy position supporting the need for further investment in flood mitigation planning and projects.
Recognitions
The King County Flood Control District was created to provide funding and policy oversight for flood risk reduction capital projects and programs in King County. The Flood Control District brings a comprehensive approach to flood management and provides funding to improve the County’s aging and inadequate flood protection facilities, including flood control facilities, capital improvement projects, and floodplain management and restoration programs. Funding is also provided for a regional flood warning center and emergency response, flood facility maintenance, public education and outreach, mapping and technical studies, citizen inquiry, and public response.
During flood events, however, it is the Flood Control District’s governmental partners at King County and the other urban and rural cities throughout the county who are responsible for emergency services, transportation, public works, housing, and other government services critical for the protection of life and property.
The King County Flood Control District would like to recognize and show appreciation for the dedicated public services provided by those who work at the USACE, King County, and at cities throughout the county. These talented professionals work long hours during flood events, occasionally at risk to their own safety, to ensure the best possible outcomes for the citizens of King County.