Precipitation Overview

Climatological data such as precipitation, evapo-transpiration, wind and temperature are usually found in university libraries and are published by the U.S. Department of Commerce National Oceanic and Atmospheric Administration (NOAA).  Precipitation data includes depth, intensity, duration, recurrence intervals, snowfall etc.  Methods of calculating precipitation for a watershed from gage data include the Thiessen polygon method, the isohyetal method, and a simple arithmetic mean.  Other forms of precipitation such as snow are also important.  Snow data can be collected by various means such as SNOTEL and snow course.