Extended Streamflow Guidance
Issued by NWS
FGUS65 KSTR 031554
TTAA00 KSLR DDHHMM
NATIONAL WEATHER SERVICE
COLORADO BASIN RIVER FORECAST CENTER
SALT LAKE CITY UT
March 3, 2017
SAN JUAN RIVER BASIN SPRING FLOOD POTENTIAL OUTLOOK
The flood potential due to snowmelt is considered higher than normal in the
San Juan Basin as of early March. This is primarily due to a signficant
snowpack that exists for early February that ranges from near 135 to 180
percent of the historical median.
Most SNOTEL sites in the San Juan River Basin have already met or exceeded
the annual spring peak snowpack that typically occurs between late March
and mid April.
Above average spring snowmelt runoff peak flows are likely. Currently no
forecast points are expected to exceed flood stage due soley to spring snow
melt. However forecast procedures do not exist for all areas and given the
significant snowpack that exists bankfull conditions and some high water
issues are possible in more flood prone areas.
Significant flooding issues tend to be more a result of summer monsoon
driven rainfall events versus spring snow melt. However a longer period of
above average runoff is anticipated this spring and any heavy rainfall that
occurs during this peak runoff period, when river channel capacities are
reduced, will dramatically increase the threat of flood related issues.
Snow typically accumulates for a few more weeks in the higher elevations of
the San Juan Basin and the flood potential threat will continue to evolve
during that time.
Specific peak flow forecasts will be availbe the week of March 6th on the
Colorado Basin River Forecast Center website at:
G. Smith/ CBRFC