This sequence of months was chosen in an effort to capture autumn soil moisture recharge, winter precipitation, and the April precipitation that often compounds snowmelt runoff flood events. Temporal variability is again quite obvious. Note that the 1996-1997 total is the largest value on record. Figure 5 summarizes May through September precipitation totals, the bulk of the growing season. On average, two thirds of annual Red River basin precipitation falls during these five months.
Interannual variability is again quite obvious.
As was the case with annual precipitation patterns, a distinct drying is obvious for the first four decades of the 20th century. Beginning in the 1940's, growing season precipitation totals dramatically increase, and then level off. The 1990's have been notable for the lack of growing seasons with below average precipitation. All rights reserved.