Wind speed readings are typically taken at approximately which height above the ground?

Wind speed readings are typically taken at approximately which height above the ground?

• A. 5 ft
• B. 20 ft
• C. 40 ft
• D. 80 ft

Answer: (B)

Wind speed readings are taken from a height above the ground that minimizes the influence of surface roughness while remaining practical for field use. In prescribed fire practice, this standard height is about 20 feet (roughly 6 meters) above ground. Measuring at this level reduces the distortion caused by vegetation, terrain, and other obstructions that slow the wind near the surface, so the reading better reflects the wind that affects fire behavior. If you read too close to the ground, the wind is slowed by the surface; if you read much higher, you’re measuring wind aloft that may not accurately represent conditions at the fire’s height. So 20 feet is the best balance.

Wind speed readings are taken from a height above the ground that minimizes the influence of surface roughness while remaining practical for field use. In prescribed fire practice, this standard height is about 20 feet (roughly 6 meters) above ground. Measuring at this level reduces the distortion caused by vegetation, terrain, and other obstructions that slow the wind near the surface, so the reading better reflects the wind that affects fire behavior. If you read too close to the ground, the wind is slowed by the surface; if you read much higher, you’re measuring wind aloft that may not accurately represent conditions at the fire’s height. So 20 feet is the best balance.