Extended Streamflow Guidance
Issued by NWS
FGUS65 KSTR 022038
NATIONAL WEATHER SERVICE
COLORADO BASIN RIVER FORECAST CENTER
SALT LAKE CITY, UTAH
MARCH 2, 2017
FLOOD POTENTIAL OUTLOOK
The flood potential for Arizona Rivers and streams has dropped to
near average at this time. It has dropped since most of the low level
snowpack has melted and the probability of a significant rain event during
the rest of this month is low. However, due to the saturated soils
currently in place, any significant storm system over the next few weeks
could cause potential flooding issues.
Seasonal October-February precipitation was 145 percent of average in
the Salt-Verde River Basin, 120 percent of average for the Gila Basin and
145 percent for the Little Colorado Basin. February precipitation was
110 percent of average in the Salt-Verde River Basin, 95 percent in the
Gila River Basin, and 110 percent of average in the Little Colorado Basin.
Basin snowpack conditions were near 105 percent of median in the
Salt-Verde River Basin, 70 percent of median in the upper Gila,
and 120 percent of median in the Little Colorado River Basin.
Modeled soil moisture states vary with most areas above average at this time
due to above average seasonal precipitation. However, the March through May
runoff volumes are primarily influenced by the frequency and magnitude of winter
Forecast neutral climate conditions suggest possible below average
precipitation through the spring. The neutral climate condition
was not accounted for in the generation of March streamflow volume forecasts.
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.