FGUS65 KSTR 072022
ESGNM 
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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

                         APRIL 7, 2023


The 2023 spring runoff flood potential due to snowmelt is high at 
this time for the San Juan river basin due to much above normal
snowpack. 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 have mean daily peak flows 
at or above the defined flood flow at the given exceedance level:

  Segment                     Threshold   Exceedance Value 
                                          (probability)
  -------                     --------    -------------
San Juan-Pagosa Springs        Bankfull          90
Animas-Durango                 Bankfull          25
Animas-Farmington              Flood             10
Mancos-Mancos                  Bankfull          90

Specific forecast procedures and flood flow levels do not exist for all streams.
Areas that typically experience high water in normal or above 
normal snow years will be susceptible during peak runoff this year. Instantaneous 
peaks can be higher than mean daily peaks, especially in headwater basins.

Precipitation in the San Juan River basin was much above average for the month 
of March and is also above average for the water year. April 1 snow water 
equivalent is much above median with many basins having record or near record
snow conditions. Temperatures have remained below normal limiting any significant
snowmelt which has resulted in much above normal snow conditions at all elevations.   


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

SUBBASIN                 MAR PRECIP     OCT-MAR PREC    APR 1 SNOWPACK
----------------------   ----------     ------------    ---------------
ABOVE NAVAJO RES             230             140             185
ANIMAS                       225             145             205 

Spring temperatures and rain events greatly affect the pattern of snowmelt 
runoff and consequently the magnitude of peak flows. 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.

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

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

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

CBRFC/Nielson