Merced River at Happy Isles

Highest listed crest 13.27 ftFlood stage 7.5 ft4 crests since 1950

The Merced River at Happy Isles crested at major flood stage 1 time among the 4 crests the National Weather Service lists from 1950 to 2023. The highest, 13.27 ft on January 2, 1997, was major flooding, 5.77 feet above flood stage. 1 other gauge on the Merced River crested above flood stage within a week of it, 1 at its own highest listed crest.

The gauge

Highest listed crest: 13.27 ft; January 2, 1997; 10,100 cubic feet per second
Flood stage: 7.5 ft; Major flooding from 13.3 ft
Crests at major: 1; 33rd of 106 gauges in California
Most recent flood crest: May 21, 2023; 8.42 ft, minor flooding
Location: Mariposa County; California
Identifiers: NWS HPIC1; USGS 11264500

Flood stages

The thresholds the National Weather Service uses for this gauge today, and how many listed crests reached each.

Flood categories, Merced River at Happy Isles

Flood stage (minor)	7.5	1	May 21, 2023	Minimal or no property damage, but possibly some public threat
Moderate flood stage	10.0	2	Dec 23, 1955	Some inundation of structures and roads near the stream
Major flood stage	13.3	1	Jan 2, 1997	Extensive inundation of structures and roads

Every listed crest

4 crests from 1950 to 2023. Filled: at or above flood stage. Hover a crest for its date and stage.

Crests at or above flood stage, by decade

These are the crests the local National Weather Service office lists for the gauge: the highest on record and recent crests. Lesser floods between them may be missing, so counts by decade are a floor.
Categories use today's flood stages. Levees, dams and channel changes since a crest can make old and new stages not directly comparable.

Highest crests

Highest listed crests, Merced River at Happy Isles

1	Jan 2, 1997	13.27	+5.77	Major	10,100
2	Dec 23, 1955	12.73	+5.23	Moderate	9,840
3	Nov 18, 1950	11.55	+4.05	Moderate	9,260
4	May 21, 2023	8.42	+0.92	Minor	—

The worst floods along the Merced River

For this gauge's highest crests, the other gauges on the Merced River that crested above flood stage within a week.

January 2, 1997: 13.27 ft here, major flooding

Pohono BridgeCA · Jan 3, 1997 · 23.43 ft · Major · its highest

December 23, 1955: 12.73 ft here, moderate flooding

Pohono BridgeCA · Dec 23, 1955 · 21.52 ft · Major

November 18, 1950: 11.55 ft here, moderate flooding

Pohono BridgeCA · Nov 19, 1950 · 20.98 ft · Major

Gauges on the Merced River

In USGS station-number order, which runs downstream within a river basin.

Flood gauges on the Merced River

Happy Isles this gauge	CA	7.5	13.27 ft, Jan 2, 1997	1
Pohono Bridge	CA	10.0	23.43 ft, Jan 3, 1997	4
Stevinson	CA	71.0	71.44 ft, Mar 21, 2023	0

Other gauges in Mariposa County

Flood gauges in Mariposa County

Pohono Bridge	10.0	23.43 ft, Jan 3, 1997	4

Mariposa County: every hazard · River floods across the country · California

NOAA National Water Prediction Service, gauge HPIC1, retrieved October 30, 2026. Stages in feet on the gauge's own datum, not elevation. Crests are as the National Weather Service lists them; preliminary values may be revised.