CNRFC - Hydrology - River Guidance - Graphical RVF

Location:

MERCED RIVER - YOSEMITE NP AT HAPPY ISLES (HPIC1)

Latitude: 37.73º N	Longitude: 119.56º W	Elevation: 4017 Feet
Location: Mariposa County in California		Bulletin Group: San Joaquin		River Group: San Joaquin

Issuance Time:

Apr 30 2025 at 7:37 AM PDT

Next Issuance:

May 01 2025 at 9:00 AM PDT

Action/Monitor: N/A

Minor Flood: 7.5 Feet

Moderate Flood: 10.0 Feet

Major Flood: 13.27 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	2,980	6.80	May 19, 2024
2023	4,980	8.42	May 23, 2023
2022	2,430	6.25	Oct 25, 2021
2021	1,410	5.02	May 7, 2021
2020	2,160	5.96	Apr 30, 2020
Historical High Stage/Flow Events (Period of Record - Aug 1915 to Present) - Ranked by Flow
1997	10,100	13.27	Jan 2, 1997
1956	9,840	12.73	Dec 23, 1955
1951	9,260	11.55	Nov 18, 1950

Location Photographs
Upstream Photo	Gage House Photo	Downstream Photo

ESRI™ Locator Map

Flood Impacts
13.27 Feet	Flood of Record: 1/2/97. $178 million in damage to Yosemite Valley.
10.0 Feet	Northside Drive at Wosky Pond, Southside Drive at Chapel Meadow, El Capitan crossover, and Sentinel crossover are impassable to vehicles.
8.2 Feet	Swinging Bridge overtops. Water on road at Northside Drive, Southsie Drive, El Capitan crossover, and Sentinel crossover.
7.5 Feet	Flood Stage. Housekeeping camp and Yosemite Valley backpacker campground begin to flood.
7.0 Feet	North Pines and Lower Pines campgrounds begin flooding.

Official 7 Day National Weather Service Forecast (CAZ324)

Tonight: Mostly cloudy with scattered rain showers and chance of thunderstorms early in the evening, then mostly cloudy with scattered rain showers and slight chance of thunderstorms late in the evening. Clear after midnight. Lows 43 to 51. Northeast winds up to 10 mph. Chance of precipitation 50 percent.

Thursday: Sunny. Slight chance of rain in the morning, then slight chance of rain and thunderstorms in the afternoon. Highs 62 to 74. Northeast winds up to 10 mph shifting to the west in the afternoon. Chance of precipitation 20 percent.

Thursday Night: Mostly clear. Lows 46 to 52. Northeast winds up to 5 mph.

Friday: Mostly sunny. A 30 percent chance of rain in the afternoon. Highs 62 to 72. East winds up to 5 mph shifting to the southwest in the afternoon.

Friday Night: Partly cloudy. Lows 44 to 50. West winds up to 10 mph shifting to the east after midnight.

Saturday: Chance of rain in the morning, then numerous rain showers in the afternoon. Highs 49 to 59. Chance of precipitation 60 percent.

Saturday Night: Colder. Mostly cloudy. Scattered rain showers in the evening, then chance of rain after midnight. Lows 36 to 42. Chance of precipitation 50 percent.

Sunday: Mostly cloudy. Chance of rain and snow likely in the morning, then scattered rain showers in the afternoon. Highs 46 to 56. Chance of precipitation 60 percent.

Sunday Night: Mostly cloudy with chance of rain in the evening, then partly cloudy after midnight. Lows 40 to 46. Chance of rain 40 percent.

Monday: Not as cool. Mostly sunny. Chance of rain in the morning. Highs 53 to 63. Chance of rain 30 percent.

Monday Night: Partly cloudy. Lows 41 to 47.

Tuesday: Warmer, sunny. Highs 60 to 70.

Tuesday Night: Partly cloudy. Lows 46 to 52.

Wednesday: Sunny. Highs 62 to 72.

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 Joaquin Valley-Hanford 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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