CNRFC - Hydrology - River Guidance - Graphical RVF

Location:

NAPA RIVER - SAINT HELENA (SHEC1)

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

Issuance Time:

Apr 30 2025 at 8:06 AM PDT

Next Issuance:

May 01 2025 at 9:00 AM PDT

Action/Monitor: 16.0 Feet

Minor Flood: 18.0 Feet

Moderate Flood: 20.0 Feet

Major Flood: 22.0 Feet

Plot Type:

Please Note:
1) Each individual timeseries plotted on the graphical river forecast can be toggled on and off by clicking the legend entry above. If the "Observed (Raw Data)" contains bad data and is toggled off, the plot will scale to the remaining timeseries.

2) At extremely low river flows, the "Observed (Raw Data)" may show readings below the lower end of the available rating table, while the "Observed (Simulated)" will only show values at the bottom of the rating table, creating a potential discrepancy between the two readings.

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

Historical Stage/Flow Data
Water Year	Peak Discharge (cfs)	Stage (feet)	Date
Most Recent 5 Years
2024*	5,290	14.07	Feb 4, 2024
2023*	7,150	16.71	Jan 9, 2023
2022*	7,560	16.82	Oct 24, 2021
2021*	178	2.26	Jan 27, 2021
2020*	696	4.31	Dec 7, 2019
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

* 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

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.

Official 7 Day National Weather Service Forecast (CAZ506)

Today: Partly cloudy in the morning then becoming sunny. Patchy fog in the morning. Highs in the mid 60s to lower 80s. South winds 5 to 10 mph.

Tonight: Mostly clear except patchy fog after midnight. Lows in the 40s to mid 50s. Southwest winds 5 to 10 mph.

Thursday: Sunny. Patchy fog in the morning. Highs in the 60s to 70s. Southwest winds 5 to 10 mph.

Thursday Night: Mostly clear except patchy fog after midnight. Lows in the mid 40s to lower 50s. West winds 5 to 15 mph.

Friday: Sunny. Highs in the lower 60s to mid 70s. West winds 5 to 10 mph increasing to 10 to 20 mph in the afternoon.

Friday Night: Mostly cloudy. Lows in the upper 40s to mid 50s.

Saturday: Mostly cloudy in the morning then becoming partly cloudy. Breezy. A slight chance of rain. Highs in the 50s to upper 60s.

Saturday Night: Mostly clear in the evening then becoming partly cloudy. Lows in the 40s to lower 50s.

Sunday through Monday Night: Mostly clear. Highs in the 60s to 70s. Lows in the mid 40s to lower 50s.

Tuesday: Partly cloudy in the morning then becoming sunny. Highs in the lower 60s to mid 70s.

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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Verification - Historical Graphical RVF
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