If a mountain is high but the air is dry, why will orographic rainfall be limited?

Correct answer: Because there will not be enough water vapour for condensation

Correct answer: A. Orographic rainfall begins when moist air is forced to rise along the slope of a mountain. Rising air expands and cools; if enough water vapour is present, the air may reach saturation, clouds may form, and precipitation may develop. Mountain height helps provide uplift and cooling, but height alone cannot create rain. If the air is very dry, it contains too little water vapour for substantial condensation, even though it is lifted high and cooled. B is wrong because mountains do not stop all rain; they can enhance rain on a windward slope and create a drier rain-shadow side. C reverses the relationship: dry air usually limits cloud water. D is wrong because rising to greater altitude generally promotes cooling through expansion. Memory cue: orographic rain needs both “lift” and “moisture.”