Extended Streamflow Guidance
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000
FGUS65 KSTR 042119
ESGCO

NATIONAL WEATHER SERVICE
COLORADO BASIN RIVER FORECAST CENTER
SALT LAKE CITY, UT


                      SPRING FLOOD POTENTIAL
             FOR THE COLORADO RIVER BASIN WITHIN COLORADO

                         MARCH 4, 2015

The 2015 spring runoff flood potential due to snowmelt is near to below
normal at this time for the Yampa/White, Upper Colorado mainstem, Gunnison,
Dolores and San Juan basins.  It should be emphasized that snow typically
accumulates into April, therefore conditions may change before the runoff
begins.

Currently, the following sites are forecast to peak at or above the flood flow
at the given exceedance level:

Colorado River near Cameo            10%

A few sites are forecast to peak above bankfull at the 25% or 10% exceedance
levels but, in general, below average peaks are expected across much of western
Colorado.  The Upper Colorado headwaters, especially the Blue River Basin,
will likely see near to above average peaks.  Keep in mind specific forecast
procedures and flood flow levels do not exist for all streams.

February precipitation was generally below average across western Colorado
with the overall basin preciptation amounts ranging between 70% and 95% of
average.  However, pockets of near to above average precipitation occurred
in the eastern San Juan and southeast Gunnison River basins due to the storm
system at the end of the month and the Upper Colorado River headwaters received
near to above average precipitation scattered throughout the month.  Seasonal
precipitation is below average at 80% in all basins with the exception of the
Upper Colorado which is at 90% of average.

Overall March 1 snow water equvialent is also below median in all basins
(between 70% and 80%) with the execption of the Upper Colorado which was at
95% of median.  However, there is much variation between individual SNOTEL sites
within each basin due to the generally warm winter which has seen precipitation
falling as rain instead of snow at times as well as some earlier than normal
melt that occurred during February at relatively high elevations.

The current volume forecasts for the April through July runoff period are
generally below average for much of the Yampa/White, Gunnison and Dolores
basins and much below average in the San Juan basin.  The Upper Colorado
mainstem basin is generally forecast to have near average runoff volumes.

Although spring temperatures affect the pattern of snowmelt runoff and
consequently the magnitude of peak flows, peak flows also 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.

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/Alcorn






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