Major Flooding Expected in Western Washington as Atmospheric River Brings Heavy Rain
Western Washington is bracing for significant rainfall as an atmospheric river is set to deliver heavy precipitation starting Tuesday. This weather phenomenon will bring between 10 to 15 inches of rain, primarily affecting the mountainous regions.
Flooding Threat in Western Washington
According to Cliff Mass, a professor of atmospheric sciences at the University of Washington, this event could be classified as a “two- to five-year occurrence.” While it is among the strongest atmospheric rivers to impact the region in recent years, it does not break historical records.
Forecasted Rainfall and Impact
The storm is expected to impact areas from Portland to Chehalis. Forecasts indicate:
- 10 to 15 inches of rain in the southern Cascades.
- 2 to 5 inches of rain in the lowlands, particularly south of Puget Sound.
Significant river flooding is anticipated, especially along the Snoqualmie, Puyallup, and Cowlitz Rivers. These bodies of water are projected to reach major flood stage, with the Snohomish and Skagit Rivers also likely to experience high levels.
Timing of Flood Conditions
The National Weather Service has issued a flood watch for much of Western Washington, which may soon transition to a flood warning. Major flooding is expected to develop on Tuesday and Wednesday, with many rivers peaking shortly after the rainfall begins. Mass advises residents to prepare quickly, particularly those in vulnerable areas.
“The key point is to avoid driving through flooded areas,” Mass warned, emphasizing safety as the waters rise.
Potential Hazards Beyond River Flooding
In addition to river flooding, urban flooding is likely due to overwhelmed storm drains. The risk of shallow landslides significantly increases as soils become saturated, posing more hazards to residents.
Long-term Water Supply Benefits
Despite the immediate flood threat, this atmospheric river may also refill crucial water reservoirs in the region. The moist soils and increased reservoir levels can aid in water supply stability for the next six months.
Although most precipitation will be in the form of rain due to high snow levels, Mass is optimistic about future snowfall building the winter snowpack essential for water resources next summer.
Preparing for the Worst
Residents have limited time to prepare for the anticipated flooding. As the situation develops, it is essential to stay informed and prioritize safety. Floodwaters can be unpredictable and dangerous, making it crucial to heed warnings and avoid flooded areas.
