The jury will remain divided on whether the 2011 season was an active one or not. The season produced a total of 19 tropical storms of which seven became hurricanes, including three major hurricanes. The 19 tropical storms represent the third-highest total (tied with 1887, 1995, and 2010) since records began in 1851 and is well above the average of 11.
Where the "lack" of storms occurred was in regards to hurricanes and major hurricanes. Only seven hurricanes formed, and, from the seven, three became major hurricanes. While these numbers are above average, they are not in the ratio form you would expect. If the season were to be in perfect ratio form, one would expect more like 12 hurricanes and 5-6 major hurricanes.
Northwesterly winds across parts of the Gulf of Mexico and western Atlantic ocean were responsible for shear and drier air. Frontal boundaries aided in some of the past summer's weather setup. Check out the satellite imagery for the entire season below.