Painted Desert (Arizona) plateau's south border the Mogollon Rim, the north border of the Arizona transition zone. Owing to the strong rain shadow of the Mogollon Rim, the Painted Desert has a cold desert climate (Köppen "BWk"), with hot, dry summers and cold, though virtually snow-free winters. The annual precipitation is the lowest in northern Arizona and in many places is lower even than Phoenix. Much of the region is accessible only by foot or unpaved road though major highways and paved roads cut across the area. The towns of Cameron and Tuba City, both on the Navajo Nation, are two major settlements.
Lockheed U-2 was kept in service due to political pressure over USAF objections, who state that the U-2 costs $2,380 per flight hour compared to the RQ-4's $6,710 as of early 2014. Critics have pointed out that the RQ-4's cameras and sensors are less capable, and a lack of all-weather operating capability; however, some of the U-2's sensors may be installed on the RQ-4. The RQ-4 Block 30's capabilities were planned to match the U-2's by FY 2016, the replacement effort is motivated by decreases in the RQ-4's cost per flying hour. The U-2's retirement was calculated to save $2.2 billion. $1.77