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: NGVD29 Metadata

Reliability of the Forecast: Based on unobstructed flow NOTE: Forecasts for the San Lorenzo River (CA) at Big Trees are issued routinely year-round.

Default Hydrograph Scale to Flood Categories   Return to Area Map

Flood Categories (in feet) Major Flood Stage: 21.76 Moderate Flood Stage: 19.5 Flood Stage: 16.5 Action Stage: 14 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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21.76	At approximately 21.76 feet discharge in the San Lorenzo River is approximately 15,000 cfs. Major flooding in the Felton Grove neighborhood occurs at this stage, with roadways several feet deep and waters inundating the approaches to the Felton Covered Bridge. Felton Covered Bridge Park begins to experience widespread flooding at shallow depths. At 15,000 cfs, the City of Santa Cruz downstream will experience more serious flooding. The flood wave may take 2-3 hours to reach Santa Cruz.
19.5	Moderate Flooding. The St. Bernard Street area in Paradise Park is under several feet of water, with below grade floodplain infrastructure several feet deeper. St. Augustine Avenue neighborhood in Paradise Park begins to flood. Flooding imminent or already occurring in the Felton Grove neighborhood. Ground stories, first floors, and garages flooded. Felton Covered Bridge Park begins to flood. NWS will issue an updated Flash Flood Warning, if not yet already issued.
16.5	Minor Flooding. Flooding is either imminent or already occurring in Paradise Park, with initial flooding in the St. Bernard Street area. NWS will issue a Flash Flood Warning, if not yet already issued.
14	Monitor Stage. Stage can rise rapidly on the San Lorenzo River, up to several feet per hour. Approximately 2.5 feet below flood levels in Paradise Park and approximately 5.5 feet below flood stage in Felton Grove. NWS may issue a Flash Flood Watch, in not yet already issued.

About This Location

Latitude: 37.044393° N, Longitude: 122.072464° W, Horizontal Datum: NAD83/WGS84 River Stage Reference Frame Gauge Height Flood Stage Uses NWS stage 0 ft 16.5 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 29 227 ft 243.5 ft Older USGS topographic maps, NGVD29 benchmarks MSL Not Available Not Available Older USGS topographic maps, MSL benchmarks Other Not Available Not Available   Current/Historical Observations: U.S. Geological Survey (USGS) Data and Site Info for Big Trees

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