Cataloging Information
Simulation Modeling
Fire Danger Rating
Weather
Fire & Climate
Recently there has been discussion in the National Wildland Fire Coordination Group (NWCG) fire danger and fire weather working teams about the impact of observations from different anemometer heights and more importantly, averaging times, on inputs to fire management systems such as National Fire Danger Rating System (Deeming and others 1977) and the Fire Behavior Prediction System (Andrews 1986, Andrews et.al. 2003). The observation standard for the NFDRS is an anemometer 6 meters (20 feet) above vegetation, averaged for 10 minutes. The National Weather Service ASOS standard is a 2-minute average at 10-meters (33 feet). The portable 'Fire RAWS' that support incidents have masts about 1.8 meters (6 feet) above the ground. Their averaging time is generally 2-minutes; however some report both 2- and 10-minute averages. This paper reports on an initial analysis of wind speeds from data collected from 3 anemometers located at 1.8, 6 and 10 meters above the ground on the same mast. Characteristics of the wind speed probability distributions and correlations between the sampling heights and averaging times are presented.