Skip Navigation Link  
NOAA logo - Click to go to the NOAA homepage National Weather Service NWS logo - Click to go to the NWS homepage
Advanced Hydrologic Prediction Service
Image background of Navigation bar Left
Bookmark and Share Navigation Bar End Cap


Web Portal Changes: The Advanced Hydrologic Prediction Service (AHPS) hosted at will be replaced by the National Water Prediction Service (NWPS), with a target of Spring 2024. Existing AHPS content and features will be preserved and expanded within NWPS. The NWS is now accepting feedback on NWPS. Please visit for more information.

Experimental National Water Center Products: Flood Inundation Mapping services are now available for 10% of the U.S. population. Please visit for more information. The National Hydrologic Discussion, Area Hydrologic Discussion, Flood Hazard Outlook, and real-time geospatial services depicting River Forecast Center and National Water Model forecasts, continue to be accessible via the URL above, as described in the StoryMap here.

DID YOU KNOW... Please try our new TEST hydrograph page link at: - Just replace “abcde” with your local hydrograph five character ID found in the lower left corner of the hydrograph.  In late March of 2024, the base URL path will become  Feedback can be provided HERE

Hydrograph River at a Glance Download
Roanoke River at Smith Mountain Lake Pool (ft)Observed: 792.76 ft at 11:58PM Nov 25, 2023Observed: 792.76 ft at 7:00AM Nov 26, 2023Observed: 792.78 ft at 7:00AM Nov 27, 2023Observed: 792.51 ft at 11:58PM Nov 27, 2023Observed: 792.51 ft at 7:00AM Nov 28, 2023Observed: 792.5 ft at 11:58PM Nov 28, 2023Observed: 792.5 ft at 7:00AM Nov 29, 2023Observed: 792.48 ft at 11:58PM Nov 29, 2023Observed: 792.29 ft at 7:00AM Nov 30, 2023Observed: 792.55 ft at 11:58PM Nov 30, 2023Observed: 792.73 ft at 7:00AM Dec 01, 2023Observed: 792.69 ft at 7:00AM Dec 02, 2023Observed: 792.84 ft at 7:00AM Dec 03, 2023Highest Observation: 792.86 ft at 7:00AM Dec 04, 2023Observed: 792.54 ft at 11:58PM Dec 04, 2023Observed: 792.54 ft at 7:00AM Dec 05, 2023SMIV2(plotting HPIRZ) Graph Created (5:50PM Dec 5, 2023)ObservedLatest observed value: 792.54 ft at 7:00 AM EST 5-Dec-2023. Flood Stage is 797 ft
Printable Image
About this graph
Tabular Data (UTC)
Tabular Data (EST)
XML Data
RSS Files
Datum: Not Available
NOTE: Forecasts are not available for the Roanoke River at Smith Mountain Lake. Only observed stages are available for this point.
Return to Area Map
Upstream Gauge - at Niagara Upstream Gauge Downstream Gauge Downstream Gauge - at Altavista
Flood Categories (in feet)
Major Flood Stage: 799
Moderate Flood Stage: 798
Flood Stage: 797
Action Stage: 796
Low Stage (in feet): 0

Historic Crests
(1) 799.79 ft on 04/27/1978
(2) 799.53 ft on 04/17/1987
(3) 799.50 ft on 11/05/1985
(4) 797.46 ft on 04/22/1992
(5) 797.42 ft on 09/29/2004
Show More Historic Crests

(P): Preliminary values subject to further review.

Recent Crests
(1) 797.42 ft on 09/29/2004
(2) 796.56 ft on 09/07/1996
(3) 797.46 ft on 04/22/1992
(4) 799.53 ft on 04/17/1987
(5) 799.50 ft on 11/05/1985
Show More Recent Crests

(P): Preliminary values subject to further review.

Low Water Records
Currently none available.
Zoom Level:16
KML Image
Gauge LocationGauge Map Marker
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.
About This Location Collapse

Latitude: 37.020000° N, Longitude: 79.530000° W, Horizontal Datum: NAD83/WGS84

River Stage
Reference Frame
Gauge Height Flood Stage Uses
NWS stage 0 ft 797 ft Interpreting hydrographs and NWS watch, warnings, and forecasts, and inundation maps
Vertical Datum Elevation
(gauge height = 0)
(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
Additional Information Collapse

Gage Photos

Gage Photo

Resources Collapse
Hydrologic Resources Additional Resources
Collaborative Agencies Collapse
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
Blacksburg Weather Forecast Office
1750 Forecast Drive
Blacksburg, VA 24060
(540) 553-8900
Ask Questions/Webmaster
Page last modified: 2-Nov-2020 7:30 PM
Privacy Policy
About Us
Career Opportunities