Pilarcitos Creek at Half Moon Bay
California — Water Level & Flood Stage
Located in San Mateo County, California on the Pilarcitos Creek. Live water level data from USGS gauge 11162630, updated every 15 minutes.
Current Water Level
Gage Height
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Streamflow
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Last Reading
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Flood Stages
Major Flood
24 ft
Moderate Flood
17 ft
Minor Flood
9.1 ft
Action Stage
7.5 ft
Flood stages defined by the National Weather Service. Gage height data from USGS Water Resources.
What Floods at Each Level
24 ft
Major flood stage. Major flooding of adjacent neighborhoods. Highway 1 backwatered and flooded at Pilarcitos Creek.
17 ft
Moderate flood stage. Homes along Willow/Pilarcitos/Oak Avenue begin to flood. Water is about 3 feet below Highway 1 bridge chord. NWS will issue a Flash Flood Warning if not yet already issued.
9.1 ft
Minor flood stage. Water begins to flood Naomi Patridge Trail. NWS will issue an urban/small stream advisory if not yet already issued.
7.5 ft
Monitor stage. Water is 1.5 feet below Naomi Patridge Trail.
Impact statements from the National Weather Service, describing what typically happens at each water level.
7-Day Water Level Chart
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Historic Crests
| Date | Stage | Flow |
|---|---|---|
| Jan 3, 1982 | 13.08 ft | 4,750 cfs |
| Jan 3, 1982 | 13.08 ft | 4,750 cfs |
| Feb 2, 1998 | 12.27 ft | 1,950 cfs |
| Feb 2, 1998 | 12.27 ft | 1,950 cfs |
About This Gauge
USGS Site
NWS LID
HMNC1
River
Pilarcitos Creek
County
San Mateo, CA
Coordinates
37.4667°N, 122.4342°W
Get Flood Alerts for Pilarcitos Creek
StormCast monitors this gauge and sends a push notification to your phone when the water level crosses into a new flood category — even at 3 AM.
Frequently Asked Questions
What is the current water level of Pilarcitos Creek at Half Moon Bay?
The Pilarcitos Creek at Half Moon Bay gauge is maintained by USGS (site 11162630) and reports water levels every 15 minutes. Visit this page to see the latest reading updated live, or download StormCast to get push alerts when levels rise.
What is flood stage for Pilarcitos Creek at Half Moon Bay?
The NWS-defined flood stage for Pilarcitos Creek at Half Moon Bay is 9.1 feet. Action stage begins at 7.5 feet. Moderate flooding starts at 17 feet, and major flooding at 24 feet.
How do I get alerts when Pilarcitos Creek rises?
Download StormCast free on Google Play, go to River Gauges, and add Pilarcitos Creek at Half Moon Bay to your watchlist. StormCast will send a push notification to your phone whenever the water level crosses into a new NWS flood category — even when your screen is off.
Where is the Pilarcitos Creek at Half Moon Bay gauge located?
The gauge is located in San Mateo County, California at coordinates 37.4667°N, 122.4342°W. USGS site number: 11162630. Data is provided by the U.S. Geological Survey and the National Weather Service.
More Resources
Source & Notes
Data provided by: US Geological Survey, Observations courtesy of U.S. Geological Survey