Web Portal Changes: The Advanced Hydrologic Prediction Service (AHPS) hosted at https://water.weather.gov will be replaced by the National Water Prediction Service (NWPS), with a target of March 2024. Existing AHPS content and features will be preserved and expanded within NWPS.

Experimental National Water Center Products: The National Hydrologic Discussion, Area Hydrologic Discussion, and Flood Hazard Outlook, and real-time geospatial services depicting River Forecast Center and National Water Model forecasts, continue to be accessible via https://www.weather.gov/owp/operations, as described in the StoryMap here.

Weather Forecast Office San Francisco Bay Area, CA

California Nevada River Forecast Center

Hydrograph

River at a Glance

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Printable Image About this graph Tabular Data (UTC) Tabular Data (PDT) Datum: Not Available Metadata

NOTE: Graphical forecasts are not available for the San Lorenzo River (CA) at Lomond Street Bridge. During times of high water, forecast crest information can be found in the text products.

Default Hydrograph Scale to Flood Categories   Return to Area Map

Flood Categories (in feet) Major Flood Stage: 28 Moderate Flood Stage: 26 Flood Stage: 24 Action Stage: 21 Low Stage (in feet): -9999 Historic Crests Currently none available. Recent Crests Currently none available. Low Water Records Currently none available.

Zoom Level:16 Legend FEMA Layer Gauge Location Disclaimer Latitude/Longitude Disclaimer: The gauge location shown in the above map is the approximate location based on the latitude/longitude coordinates provided to the NWS by the gauge owner.

Flood Impacts & Photos

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28	Major Flooding. Major flooding of homes and businesses in downtown Boulder Creek between Railroad Avenue and the San Lorenzo River and riverfront properties both up- and downstream of the town center. Highway 9 is not expected to flood at these levels, but could be damaged and/or blocked by slides and other hazards.
26	Moderate Flooding. Increased inundation of downtown Boulder Creek between Railroad Avenue and the San Lorenzo River, and of riverfront properties along Irwin Way, Camp Joy Road, and Lorenzo Avenue.
24	Minor Flooding. Lomond Street/Irwin Way begins to flood. As flood water rise, inundation may expand westward into E Lomond Street, Middleton Ave, and Junction Ave. Riverfront homes along Irwin Way, Camp Joy Road, and Lorenzo Avenue may be flooded. NWS will issue a Flash Flood Warning, if not yet already issued.
21	Monitor Stage. Water reaches bridge chord. Backwatering is possible. Flood wave travel time from Boulder Creek to the Big Trees gage in Felton, near Felton Grove, is 30 to 145 minutes. NWS may issue a Flash Flood Watch, if not yet already issued.

About This Location

Latitude: 37.125833° N, Longitude: 122.118889° W, Horizontal Datum: NAD83/WGS84 River Stage Reference Frame Gauge Height Flood Stage Uses NWS stage 0 ft 24 ft Interpreting hydrographs and NWS watch, warnings, and forecasts, and inundation maps Vertical Datum Elevation (gauge height = 0) Elevation (gauge height = flood stage) Elevation information source NAVD88 Not Available Not Available Survey grade GPS equipment, FEMA flood plain maps, newer USGS topographic maps NGVD 29 Not Available Not Available Older USGS topographic maps, NGVD29 benchmarks MSL Not Available Not Available Older USGS topographic maps, MSL benchmarks Other Not Available Not Available

Resources

Hydrologic Resources Text Products Past Precipitation Forecast Precipitation River Forecast Centers River Stage Summary California Data Exchange Center Most Recent Scheduled Reservoir Releases USGS Real-time Data for California USGS - Western Region Geologic Information Inundation Mapping Locations

Additional Resources Area Hydrographs NWS Precipitation and River Forecasting AHPS Iframes for Developers Mobile iNWS for emergency management Snow Information

Collaborative Agencies The National Weather Service prepares its forecasts and other services in collaboration with agencies like the US Geological Survey, US Bureau of Reclamation, US Army Corps of Engineers, Natural Resource Conservation Service, National Park Service, ALERT Users Group, Bureau of Indian Affairs, and many state and local emergency managers across the country. For details, please click here. NWS Information National Weather Service San Francisco Bay Area Weather Forecast Office 21 Grace Hopper Ave, Stop 5 Monterey, CA 93943-5505 (831) 656-1725 Ask Questions/Webmaster Page last modified: 2-Nov-2020 7:27 PM Disclaimer Credits Glossary Privacy Policy About Us Career Opportunities