Smoke from Plainfield fire seen on radar, explained by meteorology


A large plume of this smoke was detected by radar on Wednesday afternoon. It came from a fire in Plainfield, Indiana, at a Walmart distribution center.

You might think that radar is something on which we only see precipitation. However, the pulses sent by radar sites can pick up other particles in the air. Sometimes you can even see flocks of birds migrating. Certainly not just the rain! This time it was heavy smoke.

Another way to see this smoke moving north from the southern breeze: the correlation coefficient! Notice the blue point towards Kokomo. We typically use this radar tool in a storm capable of producing a tornado as a means of tracking debris. This radar image below can show us where the particles are different from the surrounding air (smoke debris particles).

You may have been able to see some of this smoke around your home, miles and miles from where the fire started. As the warm air rises, the winds change direction with high height above the surface. This may allow the smoke to appear curled around the horizon and correlate with winds moving more southwesterly aloft (vs. the stronger southerly breeze at the surface).

Luckily it was a warm, clear day. Warm surface temperatures were in the low 70s this afternoon. Warm air at the surface is less dense than cool air high in the sky. This warm (floating) surface air wants to rise. Along with this, it carried the smoke straight up into the sky, rather than spreading to the surface.

That’s a good thing when it comes to air quality. The problem, however, can arise overnight when surface temperatures drop and cool. A low-level inversion can occur, causing temperatures to warm with altitude rather than cool. If this happens, it could act like a plug in the atmosphere, preventing smoky air from rising and moving away from the air we breathe.


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