Lewis River river
Total streamflow across the Lewis River was last observed at 3,485 cfs, and is expected to yield approximately 6,912 acre-ft of water today; about 55% of normal. River levels are low and may signify a drought. Average streamflow for this time of year is 6,380 cfs, with recent peaks last observed on 2025-12-09 when daily discharge volume was observed at 41,600 cfs.
Maximum discharge along the river is currently at the Lewis River At Ariel reporting a streamflow rate of 2,810 cfs. This is also the highest stage along the Lewis River, with a gauge stage of 2.61 ft at this location. This river is monitored from 2 different streamgauging stations along the Lewis River, the highest being situated at an altitude of 1,085 ft, the Lewis River Above Muddy River Near Cougar.
River streamflow levels
Daily aggregate streamflow across every monitored gauge along the Lewis River. Use the range buttons to zoom in on a specific period.
Total streamflow
Sum of all monitored streamgauges · daily
Every streamgauge along the Lewis River
All 2 USGS gauges Snoflo tracks for this river, with current flow, stage, recent change, percent of normal, and the gauge's all-time min / max. Click any header to sort. Cells are heatmapped relative to the column min/max -- darker blue = higher.
| Streamgauge▾ | Streamflow (cfs)▾ | Gauge stage (ft)▾ | 24h Δ (%)▾ | % Normal▾ | Min (cfs)▾ | Max (cfs)▾ | Elevation (ft)▾ |
|---|---|---|---|---|---|---|---|
|
Lewis River Above Muddy River Near Cougar
WA
USGS 14216000
|
645 | 1.88 | -3.0 | 36% | 154 | 28,200 | 1,085 |
|
Lewis River At Ariel
WA
USGS 14220500
|
2,810 | 2.61 | -0.4 | 62% | 847 | 129,000 | 49 |
Maximum streamflow discharge by year
The single highest aggregate discharge recorded each year. Spotting the multi-year trend reveals droughts vs. wet cycles long before the headline daily flow does.
Annual peak discharge
From the river's full record · one point per water year
Streamflow elevation profile
Each bubble is one gauge along the river, plotted by current streamflow (x-axis) vs elevation (y-axis), sized by gauge stage. Reading top-to-bottom traces the river from headwaters down to its mouth -- you can see flow accumulate as elevation drops.
Elevation vs streamflow
One point per monitored gauge · bubble size = gauge stage
Lewis River
The Lewis River is located in southwestern Washington state and stretches 95 miles, originating from the western slopes of Mount Adams. Historically, the river was used by the Chinook Indians as a trading and fishing route. Today, it is primarily used for hydroelectric power and is managed by the Pacific Power and Light Company. The river is dammed in several locations, including the Merwin Dam, Yale Dam, and Swift Dam, which create reservoirs for power generation and recreational activities such as fishing, boating, and swimming. The river also supports agriculture in the region, with farms located along its banks producing crops such as berries and vegetables. The Lewis River remains an important resource for the community, providing power, recreation, and sustenance.
Track the Lewis River in the Snoflo app
Set per-gauge push alerts (e.g. "alert me when flow at the Russian R Nr Healdsburg crosses 5,000 cfs"), and Snoflo's iOS app pushes the moment USGS reports the crossing.
About the Lewis River
Where does the data for the Lewis River come from?
Streamflow and gauge stage data are sourced from the U.S. Geological Survey (USGS) National Water Information System. The aggregate flow shown at the top of the page is computed by Snoflo as the sum of all monitored gauges along the river.
How is "percent of normal" calculated?
Today's aggregate streamflow is compared to the historical average aggregate streamflow on this calendar day across the river's full record. 100% means right on average; values above 100% indicate above-normal flow (wet year); values below indicate below-normal (dry year or drought).
Why are some gauges showing very different flows?
Gauges along a river measure flow at different points: headwater gauges read what's coming off the snowpack or mountain runoff; downstream gauges integrate everything upstream, including tributary inputs. Wide spreads usually mean a tributary is contributing significantly between gauges.
What's the elevation profile chart showing?
Each bubble is one gauge along the river, plotted by streamflow (x-axis) and elevation (y-axis), sized by gauge stage. Reading top-down traces the river from headwaters to mouth -- you can see flow build as elevation drops.
Can I get alerts when a specific gauge crosses a threshold?
Yes -- alerts are managed in the Snoflo iOS app on a per-gauge basis. Open any individual streamgauge from the table above and favorite it to set a discharge threshold.