Smoke Management Meteorology

Managing smoke in ways that prevent serious impact to sensitive areas from single burns or multiple burns occurring simultaneously requires knowledge of the weather conditions that will affect smoke emissions, trajectories, and dispersion. Once smoke enters the atmosphere, its concentration at any one place or time depends on mechanisms of transport and dispersion. By transport, we mean whatever carries a plume vertically or horizontally in the atmosphere. Dispersion simply is the scattering of smoke. Vertical transport is controlled by the buoyancy of the smoke plume and stability of the atmosphere. Horizontal transport is controlled by wind. The larger the volume of space that smoke is allowed to enter and the farther it can be transported, the more disperse and less concentrated it will become.

Not only is it necessary to anticipate the weather ahead of time through the use of climatology and forecasts, but it also is useful to monitor conditions prior to and during the burn with regional, local, and on-site observations. On-site observations are helpful because air movement, and therefore smoke movement, is influenced by small variations in terrain and vegetation cover, and proximity to lakes and oceans, which off-site observations usually cannot capture. Also, forecasts are not always accurate and last-minute changes in a burn or smoke management plan may be needed. To gain more insight into the physical process of weather in wildland areas and its effect on biomass fires, refer to the section Fire Weather.

In using weather observations, forecasts, and climate summaries effectively for smoke management there are 3 general guidelines; (1) become familiar with local terrain features that influence weather patterns, (2) develop a dialogue with a reliable local weather forecaster, and (3) ask for and use climate summaries of wind and mixing height. By combining your knowledge of local weather effects, trust and communication with an experienced forecaster, and understanding of climate patterns, it is possible to fine-tune or update forecasts to meet your specific smoke management needs.

The following sections summarize how different weather and climate elements influence smoke transport and dispersion:

• Air Pressure
• Lapse Rates
• Atmospheric Stability
• Mixing Height
• Temperature Inversions
• Wind
• Atmospheric Moisture
• Weather Forecasts
• Climate