Alsea River near Tidewater

1. 28.50 ftthe flow is about 45,000 cfs and has a 1 percent chance of being exceeded in a given year (aka the 100-year flood).
2. 27.20 ftthe flow is about 41,000 cfs and has a 2 percent chance of being exceeded in any given year (aka the 50-year flood).
3. 25.50 ftthe flow is about 37,000 cfs and has a 4 percent chance of being exceeded in any give year (aka the 25-year flood).
4. 24.00 ftexpect flooding of numerous homes in the Little Albany area along with widespread flooding of numerous roads and structures along the river.
5. 23.00 ftflooding begins at 'Alsea Riviera' and 'Little Albany' between Milepost 8 and 10 near Tidewater along State Hwy 34. Widespread lowland and pasture flooding will also continue. At this level, the flow is about 31,000 cfs and has a 10 percent chance of being exceeded in any given year (aka the 10-year flood).
6. 21.50 ftthe flow is about 27,000 cfs and has a 20 percent chance of being exceeded in a given year (aka 5-year flood).
7. 21.00 ftexpect widespread flooding along the Alsea. Flood waters will likely inundate property around homes and structures in communities along the Alsea, such as Tidewater, Alsea Riviera, Little Switzerland, and Little Albany. Erosion along the Alsea and tributary creeks may also cause localized damage.
8. 20.00 ftwater begins to surround houses at the 'Little Albany' community on Highway 34 near Milepost 8. Widespread pasture and dairy land flooding can be expected. Flooding of numerous roads along and near the river occurs at this level.
9. 18.00 ftexpect minor flooding of low-lying pasture land, roads, and a few structures close to the river. The flow

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 19, 2025: 21.27 ft
• December 18, 2015: 19.40 ft
• December 21, 2014: 18.89 ft
• November 19, 2012: 18.88 ft
• January 19, 2012: 23.61 ft
• December 3, 2007: 21.85 ft
• December 30, 2005: 21.78 ft
• November 26, 1999: 20.04 ft
• December 28, 1998: 24.04 ft
• January 1, 1997: 18.21 ft

• Drift Creek of Lincoln Co. at Waldport
• Yachats River at Yachats
• E Fk Lobster Creek at Alsea
• Yaquina River at Chitwood
• Big Creek of Lane Co. at Florence
• Siuslaw River at Mapleton
• Siletz River at Siletz
• Marys River at Philomath

Forecasts by the Northwest River Forecast Center. Forecasts are issued routinely year-round.

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.