Flash Flood Advisory in Effect for Northwest Washington 8/18

Photo byNational Weather Service

Flash Flood Threat for Northwest Washington as Thunderstorms Move In

August 17, 2024 | 7:47 PM PDT

The National Weather Service (NWS) in Seattle issued a Flood Advisory for portions of northwest and west-central Washington, including areas in Clallam, Grays Harbor, Island, Jefferson, Kitsap, Mason, Skagit, King, Pierce, Snohomish, and Thurston counties. The advisory, issued at 7:47 PM PDT, remains in effect until 10:45 PM PDT this evening as a band of thunderstorms continues to sweep across the region.

Heavy Rain and Thunderstorms

The NWS reports that thunderstorms are moving rapidly through the area, bringing with them brief but intense rainfall and frequent lightning. Doppler radar and automated rain gauges indicated rainfall between 0.1 and 0.5 inches had already fallen by 7:41 PM, with an additional 0.5 to 0.8 inches expected before the storms pass. The heavy rainfall is expected to cause minor flooding in low-lying and poorly drained areas.

Areas at Risk

The advisory covers a broad area across northwest and west-central Washington, affecting several major cities, including:

• Seattle
• Tacoma
• Bellevue
• Everett
• Olympia
• Port Angeles
• Bremerton

Residents in these and surrounding areas are advised to remain alert for localized flooding, especially in areas prone to water accumulation, such as low-lying roads and poorly drained locations.

Safety Precautions

Flooding of roadways is a significant concern during this event. The NWS has issued a stern reminder: "Turn around, don’t drown" when encountering flooded roads. Most flood-related fatalities occur in vehicles, emphasizing the importance of avoiding water-covered roadways.

The NWS advises drivers and residents to remain vigilant, particularly in areas where flooding is ongoing or likely to begin soon. In addition to driving safety, residents should avoid walking or wading through flooded areas and seek higher ground if necessary.

Timeline and Expected Conditions

The advisory remains in effect until 10:45 PM PDT tonight, with the storm system expected to move out of the region thereafter. However, heavy rain and thunderstorm activity will likely persist into the late evening, contributing to additional flooding concerns.

Cities such as Auburn, Marysville, Federal Way, Puyallup, and Shelton are also expected to experience minor flooding as the storm progresses. Residents should stay informed by monitoring local news and checking the National Weather Service website for real-time updates.

Weather Watches, Warnings & Advisories are frequently updated. Please look for updates to this report from the National Weather Service, or your local news sources and NOAA All Hazards Radio.