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:

Dec 26 2025 at 2:51 PM PST

Next Issuance:

Dec 27 2025 at 9:00 AM PST

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
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	2,100	5.89	May 11, 2025
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
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
1965	9,240	11.50	Dec 23, 1964
1938	8,400	10.40	Dec 11, 1937
2018	8,060	10.09	Dec 07, 2018

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: Colder. Mostly cloudy. Snow showers, rain showers and slight chance of thunderstorms in the evening, then chance of snow and rain after midnight. Snow accumulation up to 4 inches. Total snow accumulation up to 11 inches. Snow level 4400 feet. Lows 21 to 31. North winds up to 5 mph shifting to the south after midnight. Chance of precipitation 90 percent.

Saturday: Sunny. Highs 36 to 44. East winds up to 5 mph shifting to the west in the afternoon.

Saturday Night: Mostly clear. Near steady temperature around 30. Northeast winds 5 to 10 mph.

Sunday: Not as cool. Partly sunny in the morning then clearing. Highs 43 to 51. East winds up to 10 mph.

Sunday Night: Clear. Lows 28 to 36. Northeast winds 5 to 15 mph.

Monday through Tuesday: Clear. Highs 47 to 58. Lows 31 to 41.

Tuesday Night: Mostly clear. Lows 34 to 44.

Wednesday: Mostly sunny. Highs 51 to 59.

Wednesday Night: Mostly cloudy with a 40 percent chance of rain. Lows 35 to 45.

New Years Day: Mostly cloudy with a 50 percent chance of rain. Highs 45 to 53.

Thursday Night and Friday: Rain and snow likely. Lows 34 to 42. Highs 41 to 49. Chance of precipitation 60 percent.

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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To view other verification locations, use our Historical Graphical River Forecast Interface.