Rx burning helps achieve many desired resource objectives, but nevertheless produces smoke that can cause irritation to neighbors, schools, hospitals and nursing homes. Smoke can also settle on highways causing reduced visibility that could lead to accidents. These areas are described as smoke sensitive areas.
The Rx burner could be held liable for damages caused from his/her smoke. Using fire weather forecasts, guidelines to reduce the impact of smoke have been established and should be followed.
Smoke management weather factors
- Dispersion Index - should be between 41 and 80
- Mixing Height - should be at least 1650 feet. Mixing height is described as the lid on the available volume of atmosphere. This is the height at which the smoke will begin to travel horizontally.
- Transport Wind Speed - should be at least 9 mph. Transport wind speed is the average wind speed within the mixing height
- Low Visibility Occurrence Risk Index (LVORI) - should be 6 or 7
- Turner Stability Index - describes atmospheric stability. Should be about 3 to 5
- Wind - wind is required to move smoke. The more the better to an extent. Too much wind could lead to control problems.
Residual smoke is a major problem. Be sure to have a plan in place to extinguish all smoldering stumps, logs, etc. before leaving your Rx fire.
Check for smoke sensitive areas and avoid delivering smoke in their direction. You may need to wait for a shift in wind direction before executing your burn.