Major Flood
22 ft
Current Water Level
Gage Height
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Streamflow
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Last Reading
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FLOOD STAGES
Know the flood categories.
Flood stages defined by the National Weather Service. Gage height data from USGS Water Resources.
Moderate Flood
20 ft
Minor Flood
18 ft
Action Stage
16 ft
What Floods at Each Level
24 ft
Disastrous Flooding. Widespread flooding across upper Napa Valley with travel essentially impossible. The peak water level during the flood of 12/31/2005 measured 23.6 feet.
22 ft
Major Flood Stage. Major flooding throughout the upper Napa Valley with most roads inundated, making travel extremely difficult and unsafe.
20 ft
Moderate Flood Stage. Moderate flooding of the lower portions of Silverado Trail along the reach. Inundation of low lying residential areas along the east river bank in the vicinity of Pope Street Bridge. Secondary and many primary roads inundated; most major cross roads inundated and unsafe to pass.
18 ft
Minor Flood Stage. Minor flooding of low lying agricultural areas along river begins. Low lying rural residential areas immediately adjacent to the river and some secondary roads affected.
16 ft
Monitor Stage. WFO Monterey may issue a Flood Watch-based products to cover Napa Valley regional flood potential at this stage.
Impact statements from the National Weather Service, describing what typically happens at each water level.
7-Day Water Level Chart
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Historic Crests
| Date | Stage | Flow |
|---|---|---|
| Dec 31, 2005 | 23.61 ft | 18,300 cfs |
| Feb 26, 2019 | 19.5 ft | 9,570 cfs |
| Feb 7, 2017 | 19.2 ft | 9,340 cfs |
About This Gauge
Get Flood Alerts for Napa River
StormCast monitors this gauge and sends a push notification to your phone when the water level crosses into a new flood category — even at 3 AM.
Frequently Asked Questions
What is the current water level of Napa River near St. Helena?
The Napa River near St. Helena gauge is maintained by USGS (site 11456000) and reports water levels every 15 minutes. Visit this page to see the latest reading updated live, or download StormCast to get push alerts when levels rise.
What is flood stage for Napa River near St. Helena?
The NWS-defined flood stage for Napa River near St. Helena is 18 feet. Action stage begins at 16 feet. Moderate flooding starts at 20 feet, and major flooding at 22 feet.
How do I get alerts when Napa River rises?
Download StormCast free on Google Play, go to River Gauges, and add Napa River near St. Helena to your watchlist. StormCast will send a push notification to your phone whenever the water level crosses into a new NWS flood category.
Where is the Napa River near St. Helena gauge located?
The gauge is located in Napa County, California at coordinates 38.5113°N, 122.4558°W. USGS site number: 11456000. Data is provided by the U.S. Geological Survey and the National Weather Service.
More Gauges on Napa River
On This River
Downstream: Napa River near Napa
More Resources
Source & Notes
Data provided by: US Geological Survey, Observations courtesy of U.S. Geological Survey, Observations courtesy of U.S. Army Corps of Engineers