Cap Clouds on Fuego, Acatenango and Agua Volcanoes

December 10, 2015


Photographer: Marvin Grijalva
Summary Authors: Marvin Grijalva; Jim Foster
December 2015 Viewer's Choice
Attention-getting cap clouds are shown adorning the summits of the Fuego, Acatenango and Agua volcanoes in western Guatemala as observed from the Cerro Mayor, in Pacaya volcano complex, on the morning of November 16, 2014. Cap clouds are orographic clouds that take shape when moist air pushed up mountains cools and then condenses. Before reaching the summit, the moist air isn't sufficiently cool for condensation to occur, thus the flanks of the mountains are cloud-free. Because the elevations of these three volcanoes varies only by about 700 ft (213 m), the mushroom-shaped caps all form very near their peaks. Note the colorful glory in the mist of the foreground.