Seattle, Washington –
A powerful late-summer rainstorm will drench much of Western Washington through Saturday, raising the risk of urban flooding, hazardous trail conditions, and dangerous river surges—especially in the Cascades and Olympic foothills.
According to the National Weather Service in Seattle, a frontal system will deliver 3 to 5 inches of rain in the mountains and up to 1.5 inches in the lowlands by Saturday afternoon. After weeks of dry weather, the parched ground is unlikely to absorb water quickly, leading to excessive surface runoff.
Urban areas—particularly flat roadways and intersections—could experience localized flooding. Small creeks and streams may rapidly swell, while burn scars in higher elevations carry a low but serious risk for debris flows or rockfalls. The storm is not expected to push rivers into flood stage, but some may surge to daily record crests, creating unseen hazards for boaters and hikers along riverbanks.
Trail and forest road conditions will worsen across the Cascades, where rising water levels may cut off access or cause slippery, unsafe terrain. Outdoor enthusiasts should monitor trail alerts and avoid risky crossings.
The heaviest rainfall is expected overnight into Friday morning, with unsettled conditions lasting into early Saturday evening. Additional advisories may be issued if rainfall rates increase or if flash flood conditions develop.
