Air masses formed over the Pacific Ocean are moved by prevailing westerlies where they encounter extensive north-south mountain ranges, such as the Sierra Nevada and the Cascades. Which statement best describes the outcome of this encounter between a landform and an air mass?
A) The cool, moist Pacific air heats up as it rises, releasing its precipitation as it passes the tops of the mountains, and this warm, now dry air cools as it descends on the leeward side of the range.
B) The warm, moist Pacific air rises and cools, releasing precipitation as it moves up the windward side of the range, and this cool, now dry air mass heats up as it descends on the leeward side of the range.
C) The cool, dry Pacific air heats up and picks up moisture from evaporation of the snowcapped peaks of the mountain range, releasing this moisture as precipitation when the air cools while descending on the leeward side of the range.
D) These air masses are blocked by the mountain ranges, producing high annual amounts of precipitation on the windward sides of these mountain ranges.
E) These air masses remain essentially unchanged in moisture content and temperature as they pass over these mountain ranges.

Question

Quizplus · Accepted Answer

When warm, moist Pacific air encounters mountain ranges, it is forced to rise and cool as it moves up the windward side of the range. This cooling causes the air to release precipitation. The cool, now dry air mass then continues over the range and heats up as it descends on the leeward side of the range. This can create a rainshadow effect, where the leeward side of the mountains receives much less precipitation than the windward side.

Air Masses Formed Over the Pacific Ocean Are Moved by Prevailing