National Weather Service United States Department of Commerce

Major Storm Arriving Into The Western U.S.

A major Pacific storm system will arrive into the Pacific Northwest and produce locally heavy rain, heavy mountain snow, gusty winds and a slew of marine hazards. This significant storm will dig down the West Coast over the weekend into the Southwestern U.S. For Saturday and Sunday, expect heavy to excessive rainfall along the California coast and widespread heavy mountain snow across the West. Read More >


Quick Synopsis:

Mountain snowpack and associated snow water equivalents (SWEs) across central to north central Wyoming were generally below average by late February; while SWEs across southern Wyoming basins were generally near average to slightly above  average.   SWEs at the peak snowmelt runoff elevations (8,000’ – 9.500’) were the highest across the Laramie and Lower Green Basins at 100 to 105 percent of median.  The Tongue and Powder River Drainages had SWEs at 60 to 75 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.   




 Moderate potential for flooding associated with snowmelt is expected across lower portions the Upper North Platte and Laramie Watersheds…


…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 20th of March. 



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


Monthly Wyoming Hydrologic Summary and Graphics:

(updated monthly around the 15th of every month)


Wyoming Drought Information Page:

(updated at least once a month)


Wyoming Graphical Water Supply Outlook:

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


Wyoming Average Precipitation by Basin:

 (updated monthly)


Wyoming Spring Snowmelt Runoff Flood Potential Graphic:

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


Current and Forecast Wyoming Streamflows and/or River Stages:


 The current Wyoming Spring 2016 Snowmelt Runoff Flood Potential Outlook graphic: