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Hydrograph River at a Glance Download
Twentymile River near Portage Stage (ft)Highest Observation: 22.45 ft at 9:55PM Oct 08, 2021Observed: 19.97 ft at 10:55PM Oct 08, 2021Observed: 16.32 ft at 11:55PM Oct 08, 2021Observed: 12.9 ft at 12:55AM Oct 09, 2021Observed: 11.27 ft at 1:55AM Oct 09, 2021Observed: 10.51 ft at 2:55AM Oct 09, 2021Observed: 10.21 ft at 4:55AM Oct 09, 2021Observed: 10.16 ft at 5:55AM Oct 09, 2021Observed: 10.13 ft at 6:55AM Oct 09, 2021Observed: 10.1 ft at 7:55AM Oct 09, 2021Observed: 16.07 ft at 9:55AM Oct 09, 2021Observed: 17.58 ft at 11:55AM Oct 09, 2021Observed: 11.84 ft at 1:55PM Oct 09, 2021Observed: 10.65 ft at 2:55PM Oct 09, 2021Observed: 10.14 ft at 3:55PM Oct 09, 2021Observed: 10.01 ft at 4:55PM Oct 09, 2021Observed: 9.98 ft at 5:55PM Oct 09, 2021Observed: 9.96 ft at 6:55PM Oct 09, 2021Observed: 9.94 ft at 7:55PM Oct 09, 2021Observed: 18.78 ft at 9:55PM Oct 09, 2021Observed: 20.86 ft at 10:55PM Oct 09, 2021Observed: 17.73 ft at 11:55PM Oct 09, 2021Observed: 14.36 ft at 12:55AM Oct 10, 2021Observed: 10.59 ft at 2:55AM Oct 10, 2021Observed: 9.97 ft at 4:55AM Oct 10, 2021Observed: 9.95 ft at 5:55AM Oct 10, 2021Observed: 9.89 ft at 7:55AM Oct 10, 2021Observed: 9.85 ft at 8:55AM Oct 10, 2021Observed: 9.72 ft at 9:55AM Oct 10, 2021Observed: 15.59 ft at 12:55PM Oct 10, 2021Observed: 12.87 ft at 1:55PM Oct 10, 2021Observed: 11.12 ft at 2:55PM Oct 10, 2021Observed: 10.17 ft at 3:55PM Oct 10, 2021Observed: 9.85 ft at 4:55PM Oct 10, 2021Observed: 9.75 ft at 5:55PM Oct 10, 2021Observed: 9.73 ft at 6:55PM Oct 10, 2021Observed: 9.7 ft at 7:55PM Oct 10, 2021Observed: 9.67 ft at 8:55PM Oct 10, 2021Observed: 9.89 ft at 9:55PM Oct 10, 2021Observed: 18.16 ft at 11:55PM Oct 10, 2021Observed: 15.56 ft at 12:55AM Oct 11, 2021Observed: 10.94 ft at 2:55AM Oct 11, 2021Observed: 9.81 ft at 4:55AM Oct 11, 2021Observed: 9.71 ft at 6:55AM Oct 11, 2021Observed: 9.67 ft at 7:55AM Oct 11, 2021Observed: 9.69 ft at 8:55AM Oct 11, 2021Observed: 9.72 ft at 9:55AM Oct 11, 2021Observed: 9.72 ft at 10:55AM Oct 11, 2021Observed: 10.9 ft at 11:55AM Oct 11, 2021Observed: 14.29 ft at 12:55PM Oct 11, 2021Observed: 13.38 ft at 1:55PM Oct 11, 2021Observed: 11.59 ft at 2:55PM Oct 11, 2021Observed: 10.35 ft at 3:55PM Oct 11, 2021Observed: 9.9 ft at 4:55PM Oct 11, 2021Observed: 9.81 ft at 5:55PM Oct 11, 2021Observed: 9.81 ft at 6:55PM Oct 11, 2021Observed: 9.83 ft at 7:55PM Oct 11, 2021Observed: 9.84 ft at 8:55PM Oct 11, 2021Observed: 9.86 ft at 9:55PM Oct 11, 2021Observed: 10.6 ft at 10:55PM Oct 11, 2021Observed: 15.43 ft at 11:55PM Oct 11, 2021Observed: 14.46 ft at 1:55AM Oct 12, 2021Observed: 12.16 ft at 2:55AM Oct 12, 2021Observed: 10.77 ft at 3:55AM Oct 12, 2021Observed: 10.12 ft at 4:55AM Oct 12, 2021Observed: 9.81 ft at 7:55AM Oct 12, 2021Observed: 9.8 ft at 8:55AM Oct 12, 2021Observed: 9.78 ft at 9:55AM Oct 12, 2021Observed: 9.58 ft at 10:55AM Oct 12, 2021Observed: 9.77 ft at 11:55AM Oct 12, 2021USGS Streambed Scour at Bridges in AlaskaTMRA2(plotting HGIRR) Graph Created (7:46PM Oct 15, 2021)ObservedLatest observed value: 9.77 ft at 11:55 AM AKDT 12-Oct-2021.
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Tabular Data (UTC)
Tabular Data (AKDT)
XML Data
RSS Files
Datum: Not Available
NOTE: Data is unavailable, forecasts will continue to be displayed.

NOTE: Forecasts for the Twentymile River near Portage are issued routinely during the warm season, and as needed at other times of the year.

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Flood Categories (in feet)
Major Flood Stage: 0
Moderate Flood Stage: 28
Flood Stage: 26
Action Stage: 24
Low Stage (in feet): 0

Historic Crests
(1) 25.88 ft on 10/03/2003
(2) 25.47 ft on 08/29/2001
(3) 25.02 ft on 09/07/2011
(4) 24.99 ft on 07/22/2009
(5) 24.87 ft on 10/24/2002
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(P): Preliminary values subject to further review.

Recent Crests
(1) 25.02 ft on 09/07/2011
(2) 22.74 ft on 07/10/2010
(3) 24.99 ft on 07/22/2009
(4) 23.40 ft on 09/03/2008
(5) 23.83 ft on 10/10/2006
Show More Recent Crests

(P): Preliminary values subject to further review.

Low Water Records
Currently none available.

For more information on your flood risk go to

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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.
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Latitude: 60.898056° N, Longitude: 148.921944° W, Horizontal Datum: NAD83/WGS84

River Stage
Reference Frame
Gauge Height Flood Stage Uses
NWS stage 0 ft 26 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 NULL NULL 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:

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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
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Anchorage Weather Forecast Office
6930 Sand Lake Road
Anchorage, AK 99502
(907) 266-5160
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Page last modified: 2-Nov-2020 7:26 PM
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