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FGUS65 KSTR 061827
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

                          May 6, 2013

The 2013 spring runoff flood potential due to snowmelt
is not high at this time for the Upper Green and Bear
River basins.

Currently, there are no sites forecast to peak at or
above the bank full or flood flow levels. Current forecasts
are for below average peak flows even at the 10% exceedance level.
However, it is important to emphasize that flood flows
and forecast procedures do not exist for all streams and rivers.

April precipitation was above average across southwest
Wyoming with values near of 115 and 130 percent of average
in the Upper Green and Bear River basins. Seasonal precipitation
is now 90 percent of average in both basins. As a result of below
average temperatures and above average precipitaiton in April, May
1st snow water equivalent is now near 90 to 80 percent
of average in the Upper Green and Bear River basins.

Spring temperatures highly affect the pattern of snowmelt
runoff and consequently the magnitude of peak 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,
regardless of snowpack conditions.


A list of specific spring peak flow forecasts as of May 6 are available at:
http://www.cbrfc.noaa.gov/gmap/list/list.php?type=peak

A map of the current spring peak flow forecasts is available at:
http://www.cbrfc.noaa.gov/gmap/cmap2.php?con=peak

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


CBRFC/Nielson

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