1. Wind, in miles per hour, measured at 20 feet above open, level ground or as adjusted to meet this standard to compensate for height of ground cover, uneven ground, and nearby obstructions.
2. (NFDRS) Wind, in mph, measured at 20 feet above ground, or above the average height of vegetation, and averaged over at least a 10-minute period. Also called wind velocity.
Source: National Wildfire Coordinating Group. 2012. Glossary of Wildland Fire Terminology. PMS 205. Accessed on 9 September 2013. http://www.nwcg.gov/