Extended Streamflow Guidance
Issued by NWS

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FGUS65 KSTR 031846
ESGWY
COLORADO BASIN RIVER FORECAST CENTER
NATIONAL WEATHER SERVICE SALT LAKE CITY UTAH


                     SPRING FLOOD POTENTIAL
          FOR THE GREEN AND BEAR RIVER BASINS IN WYOMING

                       FEBRUARY 3, 2017


The 2017 spring runoff flood potential due to snowmelt is
higher than normal for the Upper Green and Bear River basins in
southwest Wyoming at this time due to much above normal snow conditions
in these areas. However, it should be emphasized that snow typically
accumulates into April and May and the threat of spring flooding will largely
be determined by hydrometeorologic events that occur during the next several
months.

The snow water equivalent in the Upper Green and Bear River basins is much
above normal with many locations near or already having exceeded the annual
peak snowpack which typically occurs in April or May.

Many locations had near to or record precipitation for the month
of January. As result of a wet start to the water year, water year
precipitation (October-January) is much above average
for river basins in southwest Wyoming. Precipitation and
snow conditions as of February 1st are listed below.

PRECIPITATION AND SNOWPACK (% OF AVERAGE):

SUBBASIN                    JAN      OCT-JAN     FEB 1       JAN
                          PRECIP     PRECIP      SNOW        FLOW
----------------------    ------     -------     -----     --------
GREEN ABV FLAMING GORGE     205        170        155         130
BEAR RIVER HEADWATERS       230        165        165         110

The current volume forecasts for the April through July runoff period
are much above average for both the Upper Green and Bear River basins.

Although spring temperatures affect the pattern of snowmelt runoff and
consequently the magnitude of peak flows, peak flows may roughly correspond
to volumetric flows. It is also important to keep in mind that an extended
period of much above normal temperatures or heavy rainfall during the melt
period can cause or exacerbate flooding problems in any year.

The spring runoff flood potential will be re-evaluated in mid February and an updated
product will be issued at that time.

CBRFC/A.Nielson

$$








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