Which is a primary factor in nighttime smoke management?

• A. Topography
• B. Relative humidity
• C. Winds
• D. Temperature

Answer: (C)

Nighttime smoke management hinges on wind because the stable nocturnal atmosphere limits vertical mixing, so the smoke stays near the ground and is carried horizontally by the wind. The wind’s direction and speed determine where the plume goes and how fast it moves, making forecasted winds the key factor when planning ignition patterns and positioning to minimize impacts. Topography can modify local flow by channeling smoke through valleys or basins, but it doesn’t override the primary role of wind. Humidity and temperature affect how the plume behaves and how visible it is, but they don’t control transport as directly as wind does.