CNRFC - Hydrology - Observed River/Reservoir Conditions

NAPA RIVER - SAINT HELENA (SHEC1)

Latitude: 38.51º N	Longitude: 122.45º W	Elevation: 195 Feet
Location: Napa County in California		River Group: Russian Napa

Monitor Stage: 16.0 Feet

Flood Stage: 18.0 Feet

Observed Data Credit
	Raw streamflow data is provided by the US Geological Survey (USGS). View USGS Data for this station location.

Historical Stage/Flow Data
Note: Water Year 2025 is currently showing peak daily mean values. These will be updated to instantaneous peaks in the coming months.
Water Year	Peak Discharge (cfs)	Stage (feet)	Date
Most Recent 5 Years
2025*	4,710	13.18	Feb 04, 2025
2024*	5,290	14.07	Feb 04, 2024
2023*	7,150	16.71	Jan 9, 2023
2022*	7,560	16.82	Oct 24, 2021
2021*	178	2.26	Jan 27, 2021
Historical High Stage/Flow Events (Period of Record - Jun 2000 to Present)* - Ranked by Flow
2006*	18,300	23.61	Dec 31, 2005
1986	16,900***	18.52	Feb 17, 1986
1997	13,100	17.70	Jan 1, 1997
1956	12,600	15.17	Dec 22, 1955
1963	12,300	15.30	Jan 31, 1963
1942	11,800	14.60	Feb 06, 1942
1965	11,800	14.96	Jan 05, 1965

* Discharge affected by regulation or diversion
** Most recent continuous record back to Jun 2000 with segmented periods back to Oct 1929
*** Flood of record at old gage site

Location Photographs
Upstream Photo	Gage House Photo	Downstream Photo

ESRI™ Locator Map

Official 7 Day National Weather Service Forecast (CAZ506)

rest of Today: Partly cloudy. Highs in the upper 40s to mid 50s. West winds 10 to 20 mph.

Tonight: Rain. Lows in the 30s to mid 40s. Southeast winds 10 to 20 mph.

Thursday: Mostly cloudy in the morning then becoming sunny. Breezy. A chance of rain in the morning. A slight chance of rain in the afternoon. Highs in the mid 40s to lower 50s. Northwest winds 20 to 30 mph with gusts to around 45 mph.

Thursday Night: Mostly clear in the evening then becoming partly cloudy. Areas of frost after midnight. Lows in the upper 20s to lower 40s. Northwest winds 10 to 20 mph with gusts to around 35 mph and becoming 5 to 10 mph with gusts to around 25 mph after midnight.

Friday: Mostly cloudy. Widespread frost in the morning. Highs in the 40s to mid 50s. Northeast winds up to 5 mph and becoming southeast around 5 mph in the afternoon.

Friday Night: Partly cloudy in the evening then becoming mostly cloudy. A slight chance of rain. Lows in the 30s to lower 40s.

Saturday: Mostly cloudy. A chance of rain. Highs in the 40s to upper 50s.

Saturday Night and Sunday: Breezy, rain. Lows in the 40s to lower 50s. Highs in the mid 50s to lower 60s.

Sunday Night: Breezy. Showers and a slight chance of thunderstorms. Lows in the upper 40s to mid 50s.

Monday through Tuesday: Breezy, rain. Highs in the mid 50s to lower 60s. Lows in the mid 40s to lower 50s.

Flood Impacts
24.0 Feet	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.
22.0 Feet	Major Flood Stage. Major flooding throughout the upper Napa Valley with most roads inundated, making travel extremely difficult and unsafe.
20.0 Feet	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.
18.0 Feet	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.
16.0 Feet	Monitor Stage. WFO Monterey may issue a Flood Watch-based products to cover Napa Valley regional flood potential at this stage.

Product Disclaimer

This river graphic is not intended to serve as a substitute for official flood watches, warnings, advisories, or statements issued by the NWS San Francisco Bay Area-Monterey Weather Forecast Office. Observations are preliminary and subject to change. River levels identified as "forecast" should be consistent with those contained in official NWS products. River levels identified as "guidance" have significant uncertainty due to future weather or reservoir regulation and are provided for planning purposes only.

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