National Weather Service Advanced Hydrologic Prediction Service

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This probabilistic forecast is issued by the California Nevada River Forecast Center.

	Hydrograph			River at a Glance			Download			Probability Information Weekly Chance of Exceeding Levels Not Available Chance of Exceeding Levels During Entire Period Not Available Short-term Probabilistic Guidance (Experimental)

For official forecast click here

Experimental Short Range Forecast Uncertainty (AHPS) - External Links: Product Description Document | Customer Survey

About this graph

Forecasts for the Napa River near St. Helena are issued routinely year-round.

Return to Area Map

Downstream Gauge

Zoom Level:16

Flood Categories (in feet)

Major Flood Stage:	22
Moderate Flood Stage:	20
Flood Stage:	18
Action Stage:	16
Low Stage (in feet):	-9999

Historic Crests
(1) 23.61 ft on 12/31/2005
(2) 19.50 ft on 02/27/2019
(3) 19.20 ft on 02/07/2017
(4) 18.52 ft on 02/17/1986
(5) 18.51 ft on 03/09/1995
Show More Historic Crests

(P): Preliminary values subject to further review.

Recent Crests
(1) 16.61 ft on 03/10/2023
(2) 16.71 ft on 01/09/2023
(3) 16.82 ft on 10/24/2021
(4) 2.26 ft on 01/27/2021
(5) 4.31 ft on 12/07/2019
Show More Recent Crests

(P): Preliminary values subject to further review.

Low Water Records
Currently none available.

	Gauge Location	Disclaimer
Latitude/Longitude Disclaimer: The gauge location shown in the above map is the approximate location based on the latitude/longitude coordinates provided to the NWS by the gauge owner.

Flood Impacts & Photos

If you notice any errors in the below information, please contact our Webmaster
24	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	Major Flood Stage. Major flooding throughout the upper Napa Valley with most roads inundated, making travel extremely difficult and unsafe.
20	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	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	Monitor Stage. WFO Monterey may issue a Flood Watch-based products to cover Napa Valley regional flood potential at this stage.

Other Real-time and/or Archive Data Sources:

Collaborative Agencies

The National Weather Service prepares its forecasts and other services in collaboration with agencies like the US Geological Survey, US Bureau of Reclamation, US Army Corps of Engineers, Natural Resource Conservation Service, National Park Service, ALERT Users Group, Bureau of Indian Affairs, and many state and local emergency managers across the country. For details, please click here.

NWS Information

National Weather Service
San Francisco Bay Area Weather Forecast Office
21 Grace Hopper Ave, Stop 5
Monterey, CA 93943-5505
(831) 656-1725
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Page last modified: 2-Nov-2020 7:27 PM

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