Extended Streamflow Guidance
Issued by NWS
FGUS65 KSTR 051527
NATIONAL WEATHER SERVICE
COLORADO BASIN RIVER FORECAST CENTER
SALT LAKE CITY, UTAH
MARCH 5, 2015
FLOOD POTENTIAL OUTLOOK
The flood potential for Arizona rivers and streams is not high at this
time. It is low because of the below median snowpack and the low
probability of a significant rain event during the rest of this month.
Because the nature of flooding in Arizona is associated with rainfall
events versus snow melt it`s difficult to ascertain with much certainty
the flood threat over a season. Existing streamflow, soil, and snowpack
conditions are analyzed for their potential contribution to streamflow
levels during future rainfall events.
Seasonal October-February precipitation was 80 percent of average in
the Salt-Verde River Basin, 85 percent of average for the Gila Basin and
100 percent for the Little Colorado Basin. February precipitation was
60 percent of average in the Salt-Verde River Basin, 35 percent in the
Gila River Basin, and 85 percent of average in the Little Colorado Basin.
Basin snowpack conditions were near 35 percent of average in the
Salt-Verde River Basin, 35 percent of average in the upper Gila,
and 30 percent of average in the Little Colorado River Basin.
Modeled soil moisture states remain near to above average in the Gila and
Little Colorado Basins. Soil moisture states have improved significantly
in the Salt-Verde Basins from the late February and early March storms.
Based on these existing conditions, the Gila, Salt-Verde and Little
Colorado are likely to have a low response due to snowmelt alone.
Neutral climate conditions suggest equal chances for above or below average
precipitation. The CPC suggests a possibility of above average precipitation
in Arizona over the next several months. If these forecasts verify, there
could be an increase in runoff response due to snowmelt runoff and rainfall,
along with saturated soil moisture conditions.