Stillaguamish River at Arlington

1. 21.00 ftthe Stillaguamish River will cause severe record flooding. Deep and swift flood waters will inundate many roads including Highway 530...Marine Drive and Norman Rd and residential areas in Silvana...Norman... Florence...and Stanwood. Levees are subject to overtopping and damage. Flooding will occur all along the river including headwaters...tributaries...and other streams within and near the river basin. This stage on the Stillaguamish corresponds to a Phase 4 in the Snohomish County flood program.
2. 20.00 ftthe Stillaguamish River will cause near record major flooding. Deep and swift flood waters will inundate many roads including Highway 530 east of Arlington and at Island Crossing and most valley roads downstream of I-5 to Stanwood. Levees are subject to overtopping and damage. Flooding will occur all along the river including headwaters...tributaries...and other streams within and near the Stillaguamish River Basin. This stage corresponds to Phase 4 in Snohomish County flood program.
3. 19.00 ftthe Stillaguamish River will cause major flooding. Deep and swift waters will flood many roads including Pioneer Highway...Hwy 530...Marine Drive and Norman Rd. Swift waters will flood residential areas near Silvana...Norman...Florence and Stanwood. Flooding will occur all along the river including headwaters...tributaries...and other streams within and near the Stillaguamish River Basin. A stage of 19 feet on the Stillaguamish River corresponds to Phase 4 in the Snohomish County Flood program.
4. 18.00 ftthe Stillaguamish River will flood many roads including Hwy 530...Pioneer Highway...Marine Drive and numerous locations along Norman Rd. Swift waters will flood residential areas near Silvana...Norman and Florence. A stage of 18 feet on the Stillaguamish River corresponds roughly to Phase 3 in the Snohomish County Flood program.
5. 17.00 ftthe Stillaguamish River will cause flooding mainly in the Silvana area, along Norman Road and in Florence. A stage of 17 feet on the Stillaguamish River corresponds roughly to Phase 3 in the Snohomish County Flood program.
6. 16.00 ftthe Stillaguamish River will cause minor flooding mainly in the Silvana area...including over Pioneer Highway and along Norman Rd. A stage of 16 feet on the Stillaguamish River corresponds roughly to Phase 2 in the Snohomish County Flood program.
7. 14.00 ftthe Stillaguamish River will locally spill over its banks. Minor flooding around Silvana will occur...including over Pioneer Highway. A stage of 14 feet on the Stillaguamish River corresponds roughly to Phase 2 in the Snohomish County Flood program.

Chance of flooding, September to November

The three-month chances are the River Forecast Centers’ long-range flood outlook, issued September 22, 2026.

Most recent crests

• December 9, 2025: 16.85 ft
• January 28, 2024: 15.30 ft
• December 5, 2023: 21.34 ft
• December 25, 2022: 15.82 ft
• November 5, 2022: 17.04 ft
• March 1, 2022: 16.70 ft
• January 12, 2022: 15.86 ft
• November 29, 2021: 14.62 ft
• November 16, 2021: 15.26 ft
• November 15, 2021: 14.26 ft

• UpstreamNorth Fork Stillaguamish River at Arlington
• Stillaguamish River at I-5
• Stillaguamish River
• Stillaguamish River at Stanwood
• South Fork Stillaguamish River at Jordan Rd. Bridge
• South Fork Stillaguamish River at Granite Falls
• Oso
• Pilchuck Creek at Pilchuck Creek

Forecasts by the Northwest River Forecast Center. Forecasts are issued routinely year-round. River forecasts for this location take into account past and future precipitation. The stages/flows that will occur may be different if future rainfall is different than forecast.

Stage, flood stages, impacts and crest history from NOAA’s National Water Prediction Service. Streamflow and the daily record from the U.S. Geological Survey.