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

                      SPRING FLOOD POTENTIAL 
             FOR THE COLORADO RIVER BASIN WITHIN COLORADO

                         MARCH 6, 2023

Peak flows due to snowmelt are expected to be near to above average this spring
in the San Juan River Basin. It should be emphasized that snow typically 
accumulates into April, therefore conditions may change before the runoff 
begins. 

Spring peak flows are expected to be higher compared to the past few years 
in the San Juan River Basin. Many SNOTEL sites in the basin are near or above
the annual peak snow water equivalent(SWE)that typically occurs in April/May. 
Both water year precipitation and March 1st snow water equivalent are above
average.

PRECIPITATION (% OF AVERAGE) AND SNOWPACK (% OF MEDIAN):

SUBBASIN                 FEB PRECIP     OCT-FEB PREC    MAR 1 SNOWPACK
----------------------   ----------     ------------    ---------------
ABOVE NAVAJO RES             125             115             125
ANIMAS                       135             125             145 

It is 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.

Currently, the following sites are forecast to have mean daily peak flows 
at or above the listed threshold at the given exceedance level:

  Segment                     Threshold   Exceedance Value 
                                          (probability)
  -------                     --------    -------------
San Juan-Pagosa Springs        Bankfull         50
Animas-Farmington              Bankfull         10         
Mancos-Mancos                  Bankfull         50

Peak flow procedures do not exist for all streams. Those areas that
typically experience high water in normal or above normal
snow years will again be susceptible to similar issues during peak
runoff this year.

A list of peak flow percentile ranking and daily model guidance is 
available at:
https://www.cbrfc.noaa.gov/dbdata/station/peakgraph/list/peaklist.html?type=rank

A list of specific spring peak flow forecasts is available at:
https://www.cbrfc.noaa.gov/dbdata/station/peakgraph/list/peaklist.html

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

CBRFC/Nielson