Extended Streamflow Guidance
Issued by NWS

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FGUS65 KSTR 081708
ESGCO

NATIONAL WEATHER SERVICE
COLORADO BASIN RIVER FORECAST CENTER
SALT LAKE CITY, UT
May 8 2015


                      SPRING FLOOD POTENTIAL
             FOR THE COLORADO RIVER BASIN WITHIN COLORADO

                               MAY 2015

The 2015 spring runoff flood potential due to snowmelt is below normal at
this time for the Yampa/White, Upper Colorado mainstem, Gunnison,
Dolores, and San Juan Basins. However, recent rainfall in the Lower
Gunnison River Basin has brought river levels near the historical average
spring peak. Therefore the contribution of rainfall has most likely
provided a larger component than snow melt to spring peaks in some
areas this year.

Currently, there are no sites forecast to peak at or above the flood flow
at any exceedance levels.  In general, below average peaks are still expected
across much of western Colorado due solely to snow melt.  Keep in mind
specific forecast procedures and flood flow levels do not exist for all streams.

April precipitation was near or above average in several lower elevation areas
of western Colorado but below or much below average in higher elevations.
Driest areas included the San Juan and Yampa River Basins. Seasonal precipitation
for the October through April period remains in the 75 to 85 percent of average
range with the exception of the Colorado River headwaters where it was closer
to average.

May 1 snow water equivalent is much below median, ranging between 35%
and 65% percent, in all basins except the Upper Colorado mainstem above
Kremmling whereit is 75% of median. Snow has melted out in many areas with
only higher elvation snow remaining. Under normal spring temperature conditions
peak flows are likely to be earlier than typical due to the lack of snow.

Streamflow in April was generally below average with the exception of the
upper Colorado River mainstem where better snow conditions existed. Elsewhere
much of the snow that typically melts in April was depleted in March.

The May 1 volume forecasts for the April through July runoff period
decreased from the forecasts issued April 1 and most sites
are forecast to be below to much below average.  The only exception is in
the headwaters of the Upper Colorado mainstem above Kremmling, where near
average runoff volumes are forecast for some streams.

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. This year we
have already experienced some heavy rainfall conditions that pushed peak flows
in the lower Gunnison Basin to levels higher than expected.

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

In the table below a -1 indicated the stream is currently peaking or will
peak very soon. To best determine the time and magnitude of the peaks for
these sites refer to the daily forecasts:
http://www.cbrfc.noaa.gov


MEAN DAILY PEAK FLOW FORECASTS IN CFS
LOCATION                   FLOOD     FCST   FORECAST FLOWS
                            FLOW     DATE      90%    75%    50%    25%    10%
--------------------------------------------------------------------------------
YAMPA - STEAMBOAT SPRINGS   5930 2015-05-01                   -1
ELK - MILNER, NR            5750 2015-05-01                   -1   2000   2500
YAMPA - MAYBELL, NR        21200 2015-05-01                   -1
LITTLE SNAKE - LILY, NR     -999 2015-05-01                   -1
YAMPA - DEERLODGE PARK      -999 2015-05-01                   -1
WHITE - MEEKER, NR          8324 2015-05-01                   -1   1800   2000
WHITE - WATSON, NR          -999 2015-05-01                   -1   1800   2000
SNAKE - MONTEZUMA, NR       2180 2015-05-01    300    320    350    400    500
TENMILE CK - FRISCO, N TE   1530 2015-05-01    550    600    650    800    850
STRAIGHT CK - LASKEY GULC    440 2015-05-01     65     70     80    100    120
EAGLE - GYPSUM, BLO         6550 2015-05-01   1600   1800   2200   2800   3200
COLORADO - DOTSERO, NR     16900 2015-05-01   4500   4800   5500   7000   9000
CRYSTAL - REDSTONE, NR, A   3130 2015-05-01    900    950   1100   1250   1500
ROARING FORK - GLENWOOD S  17200 2015-05-01   2500   3000   3500   4500   5000
COLORADO - CAMEO, NR       26000 2015-05-01   8000   9000  10500  13500  16500
EAST - ALMONT               3170 2015-05-01    900   1150   1200   1350   1420
NF GUNNISON - SOMERSET, N  13870 2015-05-01                    0
SURFACE CK - CEDAREDGE      1410 2015-05-01                    0
GUNNISON - GRAND JUNCTION  19520 2015-05-01                   -1
DOLORES - RICO, BLO         1780 2015-05-01    490    510    570    630    690
DOLORES - DOLORES           7130 2015-05-01   1350   1450   1600   1800   1900
SAN MIGUEL - PLACERVILLE,   3190 2015-05-01    730    780    840    920   1000
COLORADO - CO-UT STATE LI  46200 2015-05-01  11000  11500  12500  17000  21000
SAN JUAN - PAGOSA SPRINGS   5000 2015-05-01                   -1
ANIMAS - DURANGO           10200 2015-05-01   2400   2600   2700   3100   3500
ANIMAS - FARMINGTON         8810 2015-05-01   2300   2600   2800   3200   3700

CBRFC/Alcorn-Smith




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