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Hydrograph River at a Glance Download
Fortymile River at Mosquito Fork Stage (ft)Observed: 9.34 ft at 4:00PM Mar 13, 2023Observed: 9.51 ft at 10:00PM Mar 13, 2023Observed: 9.65 ft at 4:00AM Mar 14, 2023Observed: 9.36 ft at 11:00AM Mar 14, 2023Observed: 9.36 ft at 4:00PM Mar 14, 2023Observed: 9.43 ft at 10:00AM Mar 16, 2023Observed: 9.28 ft at 4:00PM Mar 16, 2023Observed: 9.7 ft at 10:00PM Mar 16, 2023Observed: 9.7 ft at 4:00AM Mar 17, 2023Observed: 9.4 ft at 10:00AM Mar 17, 2023Observed: 9.58 ft at 4:00PM Mar 17, 2023Observed: 9.62 ft at 10:00PM Mar 17, 2023Observed: 9.67 ft at 4:00AM Mar 18, 2023Observed: 9.66 ft at 10:00AM Mar 18, 2023Observed: 9.51 ft at 4:00PM Mar 18, 2023Highest Observation: 9.72 ft at 10:00PM Mar 18, 2023Observed: 9.5 ft at 10:00AM Mar 19, 2023Observed: 9.4 ft at 4:00PM Mar 19, 2023Observed: 9.62 ft at 10:00PM Mar 19, 2023FMKA2(plotting HGIRZ) Graph Created (10:02AM Mar 20, 2023)ObservedLatest observed value: 9.62 ft at 10:00 PM AKDT 19-Mar-2023. Flood Stage is 16 ft
About this graph
Tabular Data (UTC)
Tabular Data (AKDT)
XML Data
RSS Files
Datum: Not Available
NOTE: NWS gage operated on a seasonal basis. No data available during winter months.

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

NOTE: Forecasts for the Fortymile River at Mosquito Fork are issued routinely during the warm season, and as needed at other times of the year.

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Downstream Gauge Downstream Gauge - at West Fork
Flood Categories (in feet)
Major Flood Stage: 0
Moderate Flood Stage: 27
Flood Stage: 24
Action Stage: 22
Low Stage (in feet): -9999

Historic Crests

(P): Preliminary values subject to further review.

Recent Crests

(P): Preliminary values subject to further review.

Low Water Records
Currently none available.
Zoom Level:14
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.
Flood Impacts & Photos Collapse
If you notice any errors in the below information, please contact our Webmaster
28.18 Cement pad in front of outhouse in parking lot gets covered with water.
26.8 Water inundates middle of parking lot. Moderate flood stage
24 Water covers right downstream low spot in private road along stream. Minor flood stage.
22.44 Right upstream bankfull.
17.5 Left upstream bankfull near parking lot.
16.37 High water mark on left upstream bank June 2000.
(1) Bridge
(2) Downstream
(3) Upstream
(4) Fortymile River at Mosquito Fork looking upstream, Stage = 12.81 ft
(5) Fortymile River at Mosquito Fork looking downstream, Stage = 12.81 ft
About This Location Collapse

Latitude: 64.066111° N, Longitude: 141.997222° W, Horizontal Datum: NAD83/WGS84

River Stage
Reference Frame
Gauge Height Flood Stage Uses
NWS stage 0 ft 24 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 1608.55 ft 1632.55 ft 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
Other Not Available Not Available  
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Long-term Hydrograph
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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
National Weather Service
Fairbanks Weather Forecast Office
UAF-IARC Bldg. P.O. Box 757345
Fairbanks, AK 99775-7345
(907) 458-3700
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Page last modified: 2-Nov-2020 7:26 PM
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