Initial 2017 Wyoming Spring Snowmelt Flood Potential Outlook---issued February 17

Quick Synopsis:

Mountain snowpack and associated snow water equivalents (SWEs) across central through western Wyoming were generally much above average by the middle of February; while SWEs across basins on southeastern Wyoming were generally above average. SWEs at the peak snowmelt runoff elevations (8,500’ – 10.000’) were the highest across the Wind and the Upper Green Basins at 175 to 185 percent of median. The Tongue and Powder River Drainages had SWEs at 85 to near 100 percent of median at the peak snowmelt runoff elevations.

This outlook is based on various diverse hydrological factors such as snow water equivalents (SWEs) in the mountain snowpack, basin morphology (i.e. how basins respond to snowmelt runoff), antecedent soil moisture, amount of bark beetle kill, low elevation snow depths, and likely temperature and precipitation trends during late spring/early summer.

HIGHLIGHTS:

…Moderate to High potential for flooding associated with snowmelt is expected across lower portions the of the Little and Big Wind Watersheds…

…Moderate potential for flooding associated with snowmelt is expected across the upper to middle portions the of the Little and Big Wind Watersheds, the middle portions of the Upper Green Drainage, the lower potions of the North/South Forks of the Shoshone Basin, and portions of the Snake River Watershed.

…All other of headwater basins across Wyoming can expect a generally Low potential for flooding due to springtime snowmelt...

The next outlook will be issued around the middle of March.

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Other hydrological information for Wyoming can be found at the NOAA hydrology website:

https://www.weather.gov/riw/local_hydrology

Monthly Wyoming Hydrologic Summary and Graphics:

(updated monthly around the 15^th of every month)

https://www.weather.gov/media/riw/hydro/hydro_report.pdf

Wyoming Drought Information Page:

(updated at least once a month)

https://www.weather.gov/riw/drought

Wyoming Graphical Water Supply Outlook:

(updated by the 10^th of every month—January-June)

https://www.weather.gov/images/riw/hydro/watersupply.png

Wyoming Average Precipitation by Basin:

(updated monthly)

https://www.weather.gov/images/riw/hydro/wyomingprecip.png

Wyoming Spring Snowmelt Runoff Flood Potential Graphic:

(updated around the 20^th of the month---February-May)

https://www.weather.gov/images/riw/hydro/floodoutlook.png

Current and Forecast Wyoming Streamflows and/or River Stages:

https://water.weather.gov/ahps2/index.php?wfo=RIW

https://water.weather.gov/ahps2/index.php?wfo=CYS

https://waterdata.usgs.gov/wy/nwis/rt

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The current Wyoming Spring 2017 Snowmelt Runoff Flood Potential Outlook graphic:

Significant Severe Weather, Dangerous Heat and Extremely Critical Fire Weather Conditions Across the Southern U.S.

Initial 2017 Wyoming Spring Snowmelt Flood Potential Outlook---issued February 17

Quick Synopsis:

HIGHLIGHTS: