Briefly sketch or describe the conditions that lead to the formation of a Santa Ana wind. Is the Santa Ana wind dry or moist, warm or cold?

Question

What will be the ideal response?

Answer 1

ANSWER: Santa Ana wind is a warm, dry wind that blows downhill from the east or northeast into southern California. As the air descends from the elevated desert plateau, it funnels through mountain canyons in the San Gabriel and San Bernardino Mountains, finally spreading over the Los Angeles Basin and San Fernando Valley and out over the Pacific Ocean. The wind often blows with exceptional speed—occasionally over 90 knots—in the Santa Ana Canyon (the canyon from which it derives its name). These warm, dry winds develop as a region of high pressure builds over the Great Basin. The clockwise circulation around the anticyclone forces air downslope from the high plateau. Thus, compressional heating provides the primary source of warming. The air is dry, since it originated in the desert, and it dries out even more as it is heated. As the wind rushes through canyon passes, it lifts dust and sand and dries out vegetation, which sets the stage for serious brush fires, especially in autumn, when chaparral-covered hills are already parched from the dry summer.