STUDIES OF FOG EVENTS AT 2 CLOUD FORESTS NEAR CARACAS, VENEZUELA .1. FREQUENCY AND DURATION OF FOG

Fog incidence was examined at two Venezuelan cloud forests directly adjacent to the Caracas Valley (Altos de Pipe, 1750 m elevation, and El Avila National Park, 2150 m) during the wet and dry seasons of 1989-1990. Fog frequency was extremely high during the morning hours; fog was present up to 92% of the time at 0800 h. Fog also was found to be a very important hydrological input in these high altitude forests during both the wet and dry seasons. Preliminary measurements show that fog deposition accounts for an estimated 35 and 71% of annual precipitation at Altos de Pipe and El Avila, respectively, with fog occurring up to 326 days a year.