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 Portland, OR

Northwest River Forecast Center

Hydrograph

River at a Glance

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Probability Information Weekly Chance of Exceeding Levels Chance of Exceeding Levels During Entire Period Short-term Probabilistic Guidance (Experimental)

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Printable Image About this graph Tabular Data (UTC) Tabular Data (PDT) Datum: NGVD29 Metadata

NOTE: Forecasts for the Johnson Creek near Sycamore are issued routinely year-round.

Default Hydrograph Scale to Flood Categories   Return to Area Map

Upstream Gauge

Downstream Gauge

Flood Categories (in feet) Major Flood Stage: 14 Moderate Flood Stage: 0 Flood Stage: 11 Action Stage: 10 Low Stage (in feet): -9999 Historic Crests (1) 15.33 ft on 12/07/2015 (2) 15.30 ft on 11/19/1996 (3) 14.69 ft on 01/02/2009 (4) 14.68 ft on 12/22/1964 (5) 14.50 ft on 12/01/1937 Show More Historic Crests (P): Preliminary values subject to further review. Recent Crests (1) 15.33 ft on 12/07/2015 (2) 13.21 ft on 01/19/2012 (3) 14.69 ft on 01/02/2009 (4) 11.90 ft on 12/03/2007 (5) 11.28 ft on 12/14/2003 Show More Recent Crests (P): Preliminary values subject to further review. Low Water Records (1) 0.33 ft on 08/14/1940 (2) 0.65 ft on 08/18/1959 (3) 0.70 ft on 09/06/1955 Show More Low Water Records For more information on your flood risk go to www.floodsmart.gov. Show FEMA's National Flood Hazard Layers FEMA's National Flood Hazard Layers not showing? Why aren't the FEMA National Flood Hazard Layers showing on the ESRI Map? Possible reasons: There are no FEMA National Flood Hazard Layers for the location which you are viewing on ESRI Maps. The FEMA Web Mapping Service (WMS) is down. Note: Your zoom level may have changed. ESRI's zoom levels must be between 14 and 16 to show National Flood Hazard layers.

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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14	expect widespread flooding of residential and commercial areas along Johnson Creek.
13	expect flooding to begin at numerous locations along Johnson Creek. Evacuations of several homes have historically taken place at this and higher stages.
11	minor flooding begins along Johnson Creek between SE 92nd Street to SE 122nd Street and between Johnson Creek and SE Harold Street.
Photos (1) Downstream view (2) Downstream view with staff gage (3) Gage house (4) Upstream view

About This Location

Latitude: 45.477500° N, Longitude: 122.508333° W, Horizontal Datum: NAD83/WGS84 River Stage Reference Frame Gauge Height Flood Stage Uses NWS stage 0 ft 11 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 29 228.47 239.47 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 Sycamore

Additional Information

Archived/Historical Data at USACE DataQuery 10-day Forecast/Trend, Northwest River Forecast Center

Resources

Hydrologic Resources Text Products Past Precipitation Forecast Precipitation River Forecast Centers River Stage Summary Text Table Temp & Precip Forecasts 3-Day Detailed Precip Forecast 10-Day Temp & Precip Outlook Lewis Dams - USGS data (scroll down to Lewis basin) Lower Columbia Reservoir and River conditions USACE DataQuery USGS WaterWatch Oregon USGS WaterWatch Washington USGS River Temperatures & Water Quality Oregon USGS River Temperatures & Water Quality Washington Oregon Water Resources Dept - Surface Water Data USGS Oregon river levels USGS Washington river levels

Additional Resources Area Hydrographs NWS Precipitation and River Forecasting AHPS Iframes for Developers Mobile iNWS for emergency management Snow Data NRCS SNOTEL data map interface USACE Portland District Reservoirs USBR PacNW Reservoirs Oregon Drought Information National Drought 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 Portland Weather Forecast Office 5241 NE 122nd Avenue Portland, OR 97230-1089 (503) 261-9246 Ask Questions/Webmaster Page last modified: 2-Nov-2020 7:27 PM Disclaimer Credits Glossary Privacy Policy About Us Career Opportunities