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Hydrograph River at a Glance Download
Tonsina River at Richardson Hwy Bridge Stage (ft)Observed: 10.03 ft at 3:00PM Jan 27, 2023Observed: 10.02 ft at 9:00PM Jan 27, 2023Observed: 10.13 ft at 3:00AM Jan 28, 2023Highest Observation: 10.16 ft at 9:00AM Jan 28, 2023Observed: 10.12 ft at 3:00PM Jan 28, 2023Observed: 10.13 ft at 9:00PM Jan 28, 2023Observed: 10.14 ft at 10:00AM Jan 29, 2023Observed: 10.15 ft at 3:00PM Jan 29, 2023Observed: 9.66 ft at 9:00PM Jan 29, 2023Observed: 9.67 ft at 9:00AM Jan 30, 2023Observed: 10.11 ft at 3:00PM Jan 30, 2023Observed: 10.12 ft at 9:00PM Jan 30, 2023Observed: 10.1 ft at 3:00PM Jan 31, 2023Observed: 10.1 ft at 9:00PM Jan 31, 2023Observed: 9.76 ft at 9:00AM Feb 01, 2023Observed: 9.73 ft at 3:00PM Feb 01, 2023Observed: 9.92 ft at 9:00PM Feb 01, 2023Observed: 9.92 ft at 9:00AM Feb 02, 2023Observed: 9.9 ft at 3:00PM Feb 02, 2023Observed: 9.93 ft at 9:00PM Feb 02, 2023TONA2(plotting HGIRZ) Graph Created (11:02AM Feb 3, 2023)ObservedLatest observed value: 9.93 ft at 9:00 PM AKST 2-Feb-2023. Flood Stage is 12.5 ft
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About this graph
Tabular Data (UTC)
Tabular Data (AKST)
XML Data
RSS Files
Datum: Not Available
NOTE: Stage may be affected by ice.

NOTE: Gage data do not meet the quality standards of USGS gages.

NOTE: Forecasts for the Tonsina River at Richardson Hwy Bridge 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: 13
Flood Stage: 12.5
Action Stage: 11.5
Low Stage (in feet): -9999

Historic Crests
(1) 14.57 ft on 10/11/2006 (P)
(2) 13.44 ft on 06/30/2000
(3) 13.23 ft on 06/25/2001
(4) 13.00 ft on 09/22/1995
(5) 13.00 ft on 06/09/1998
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(P): Preliminary values subject to further review.

Recent Crests
(1) 10.50 ft on 06/21/2021
(2) 10.27 ft on 06/12/2017 (P)
(3) 10.59 ft on 06/21/2016 (P)
(4) 12.15 ft on 06/25/2012 (P)
(5) 10.88 ft on 06/05/2011
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(P): Preliminary values subject to further review.

Low Water Records
Currently none available.
Zoom Level:11
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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.
Flood Impacts & Photos Collapse
If you notice any errors in the below information, please contact our Webmaster
25.5 Bridge Low Cord
12 High water level -- Class IV whitewater in Tonsina River canyon
11.5 Bankfull -- stage associated with a flow (5100 cfs) having a recurrence interval of ~2 years
10 Medium water level -- Class III+ whitewater in Tonsina River canyon
9 Low water level -- Class III whitewater in Tonsina River canyon
(1) Looking Downstream
(2) Looking Upstream
(3) Flood 10/10/2006
(4) Flood 10/10/2006
(5) Flood 10/10/2006
(6) Bridge
(7) Downstream left bank stage 9.96ft
(8) Downstream right bank stage 9.96ft
About This Location Collapse

Latitude: 61.661389° N, Longitude: 145.183889° W, Horizontal Datum: NAD83/WGS84

River Stage
Reference Frame
Gauge Height Flood Stage Uses
NWS stage 0 ft 12.5 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 1500 ft 1513.5 ft Older USGS topographic maps, NGVD29 benchmarks
MSL Not Available Not Available Older USGS topographic maps, MSL benchmarks
Other Not Available Not Available  
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NWS Information
National Weather Service
Anchorage Weather Forecast Office
6930 Sand Lake Road
Anchorage, AK 99502
(907) 266-5160
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