What is the primary climatic characteristic that governs the heavy precipitation experienced in the mountainous terrain of Arunachal Pradesh during the monsoon season?

💡 Solution & Explanation

The extreme rainfall in Arunachal Pradesh is fundamentally caused by orographic lifting, where warm and moisture-laden southwest monsoon winds from the Bay of Bengal are forced to rise abruptly over the steep, high-altitude ranges of the Himalayas, causing rapid adiabatic cooling and heavy precipitation. Continental polar air masses do not influence this tropical summer pattern, and upper valley depressions are secondary factors compared to the dominant relief-induced condensation. This region receives some of the highest annual rainfall totals in the Indian subcontinent.