Extended Streamflow Guidance
Issued by NWS
FGUS65 KSTR 171834
NATIONAL WEATHER SERVICE
COLORADO BASIN RIVER FORECAST CENTER
SALT LAKE CITY, UT
SPRING FLOOD POTENTIAL
FOR THE COLORADO RIVER BASIN WITHIN COLORADO
FEBRUARY 17, 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 it is early in
the snow accumulation season and conditions could change quite a bit before
the runoff begins.
January precipitation was much below average across all of western Colorado.
The highest percentage occurred in the San Juan Basin at 70 percent of average
while the rest of the basins were between 40 and 50 percent of average.
Seasonal precipitation is near to below average and ranges from 70 percent of
average in the San Juan basin to 95 percent of average in the Upper Colorado
mainstem basin. February 1st snow water equivalent is between 65 and 100
percent of median. The Upper Colorado mainstem has the best snowpack right
now at near average, but the rest of the basins are below to much below average.
As of February 17th, the monthly precipitation is below to much below
average, with a sharp north to south decrease. The Yampa/White and Upper
Colorado mainstem have had near 80 percent and near 70 percent of average
monthly precipitation to date, respectively, while the Gunnison, Dolores, and
San Juan basins have had only 10-20 percent of monthly precipitation to date.
Snow water equivalent as of February 17th is below to much below median
with a few exceptions: the Blue River Basin snowpack is 114 percent of median
and the Eagle River Basin is near median. The Yampa/White, Gunnison, and the
rest of the Upper Colorado mainstem are generally between 70 and 80 percent
of median, while the Dolores and San Juan basins have between 55 and 60
percent of median snow water equivalent at this time.
The February 1 volume forecasts for the April through July runoff period are
generally near to below average for much of the Yampa/White, Upper Colorado
mainstem, and Gunnison basins, although within those areas sub-basins such as
the Little Snake, Plateau Creek and North Fork Gunnison are forecast to be much
below average at this time. The forecasts in the Dolores Basin are
below average and the San Juan basin forecasts are much below average.
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.