Extended Streamflow Guidance
Issued by NWS
FGUS65 KSTR 051618
NATIONAL WEATHER SERVICE
COLORADO BASIN RIVER FORECAST CENTER
SALT LAKE CITY, UTAH
JANUARY 5, 2017
FLOOD POTENTIAL OUTLOOK
The flood potential for Arizona Rivers and streams is near average
at this time.
Because the nature of flooding in Arizona is associated with rainfall
events versus snow melt it`s difficult to determine 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-December precipitation was 135 percent of average in
the Salt-Verde River Basin, 105 percent of average for the Gila Basin and
140 percent for the Little Colorado Basin. December precipitation was
195 percent of average in the Salt-Verde River Basin, 160 percent in the
Gila River Basin, and 195 percent of average in the Little Colorado Basin.
January 1st snowpack conditions was 85 percent of average in the
Salt-Verde River Basin, 15 percent of average in the upper Gila,
and 95 percent of average in the Little Colorado River Basin.
Modeled soil moisture states were overall much below average at the
beginning of the water year. However, Conditions have improved by the
end of December. January through May runoff volumes are primarily
influenced by the frequency and magnitude of winter rain events.
Due to the improved soil moisture conditions, average snow water
equivalents and the presence of an active weather pattern not typically
seen in a La Nina year, the flood potential for Arizona is near average.