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* WHAT...Snow expected. Total snow accumulations between 3 and 7 inches. * WHERE...Castle Rock. * WHEN...From 3 PM this afternoon to noon MDT Saturday. * IMPACTS...Snow covered roads could make travel hazardous. The hazardous conditions will impact the Friday evening commute.
Total streamflow across the
Willamette River
was last observed at
119,800
cfs, and is expected to yield approximately
237,620
acre-ft of water today; about 103%
of normal.
Average streamflow for this time of year is
116,433 cfs,
with recent peaks last observed
on
2019-04-13 when daily discharge volume was observed at
674,700 cfs.
Maximum discharge along the river is currently at the
Willamette River At Portland
reporting a streamflow rate of 34,900 cfs.
However, the streamgauge with the highest stage along the river is the
Willamette River At Newberg
with a gauge stage of 59.18 ft.
This river is monitored from 6 different streamgauging stations along the Willamette River, the highest being situated at an altitude of 294 ft, the
Willamette River At Harrisburg.
| Last Updated | 2025-04-18 |
| Discharge Volume | 237,620 ACRE-FT |
| Streamflow |
119,800.0 cfs
+2500.0 cfs (+2.13%) |
| Percent of Normal | 102.89% |
| Maximum |
674,700.0 cfs
2019-04-13 |
| Seasonal Avg | 116,433 cfs |
The Willamette River ( (listen) wil-AM-it) is a major tributary of the Columbia River, accounting for 12 to 15 percent of the Columbia's flow. The Willamette's main stem is 187 miles (301 km) long, lying entirely in northwestern Oregon in the United States. Flowing northward between the Oregon Coast Range and the Cascade Range, the river and its tributaries form the Willamette Valley, a basin that contains two-thirds of Oregon's population, including the state capital, Salem, and the state's largest city, Portland, which surrounds the Willamette's mouth at the Columbia.
Originally created by plate tectonics about 35 million years ago and subsequently altered by volcanism and erosion, the river's drainage basin was significantly modified by the Missoula Floods at the end of the most recent ice age. Humans began living in the watershed over 10,000 years ago. There were once many tribal villages along the lower river and in the area around its mouth on the Columbia. Indigenous peoples lived throughout the upper reaches of the basin as well.
Rich with sediments deposited by flooding and fed by prolific rainfall on the western side of the Cascades, the Willamette Valley is one of the most fertile agricultural regions in North America, and was thus the destination of many 19th-century pioneers traveling west along the Oregon Trail. The river was an important transportation route in the 19th century, although Willamette Falls, just upstream from Portland, was a major barrier to boat traffic. In the 21st century, major highways follow the river, and roads cross it on more than 50 bridges.
Since 1900, more than 15 large dams and many smaller ones have been built in the Willamette's drainage basin, 13 of which are operated by the U.S. Army Corps of Engineers (USACE). The dams are used primarily to produce hydroelectricity, to maintain reservoirs for recreation, and to prevent flooding. The river and its tributaries support 60 fish species, including many species of salmon and trout; this is despite the dams, other alterations, and pollution (especially on the river's lower reaches). Part of the Willamette Floodplain was established as a National Natural Landmark in 1987 and the river was named as one of 14 American Heritage Rivers in 1998.
