Extended Streamflow Guidance
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1
000
FGUS65 KSTR 041725
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 4, 2018


The 2018 spring runoff flood potential due to snowmelt is not
high in the Green and Bear Rivers Basins in southwest Wyoming.
The snowpack is above average in the area above Fontenelle
Reservoirs and near or below average for other parts of the Upper
Green River and Bear River Basins.

Specific forecast procedures and flood flow levels do not exist
for all streams. Currently, there are no sites forecast to peak
at flood flows. However, we are expecting high flows at the
Green River nr LaBarge.

April precipitation was average above Fontenelle and in the
Bear River Headwaters, and 90% of normal above Flaming
Gorge Reservoir. Water year precipitation (October-April) is
currently below average for river basins in southwest Wyoming
except above Fontenelle, which is near average. Precipitation
and snow conditions as of May 1st are listed below.

PRECIPITATION AND SNOWPACK (% OF AVERAGE):

SUBBASIN                     APR    OCT-APR     MAY 1
                          PRECIP     PRECIP      SNOW
----------------------    ------     -------     -----
GREEN ABV FONTENELLE        100        100        120
GREEN ABV FLAMING GORGE      90         90        100
BEAR RIVER HEADWATERS       100         90         65


Although spring temperatures affect the pattern of snowmelt runoff
and consequently the magnitude of peak flows, peak flows may roughly
correspond to volumetric flows. Current volume forecasts for the
April through July runoff period are above average for Fontenelle
Reservoir inflow, near average for Flaming Gorge Reservoir inflow,
and below average in other areas of southwest Wyoming.

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 May
and an updated product will be issued at that time.

A list of specific spring peak flow forecasts are available at:
http://www.cbrfc.noaa.gov/rmap/peak/peaklist.php

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

CBRFC/A.Nielson, Pat Kormos

$$



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.