Shade to sun

Raining – but where? One of the surprising features of small islands and montane environments is the strong variability of climate with elevation. Here, you see a view from approximately 500 m elevation above sea level – the plain is sunny and clear, but the higher-elevation forest is shrouded in clouds.

Here is another view, looking from sea level up into the mountains. Sun illuminates this shopping plaza (once a marsh) but heavy rain falls in the rainforest, keeping us consistently wet while working.

Why such a dramatic change in climate over such a short distance? Elevational control of climate. Moist warm air is transported west from the ocean to the coast, where it is deflected up the mountains. As it rises, it necessarily cools and condensation of water vapor occurs. Heavy precipitation at intermediate elevations is the result. At higher elevations, the air has lost its moisture and becomes too cold to store more, so very high sites tend to be sunny, cold, and dry. This rain band is observed on coastal mountains worldwide.

A side-effect of this phenomenon is beautiful sunny mornings at the beach – we took a short break from the clouds for some yoga!

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