A low morning fog crept onto the airport as I cleared a CRJ-900 regional jet for takeoff. The RJ lifted, passing just above the vaporous wall, and I switched him to Departure. I waited, watching for something I dealt with every day as an air traffic controller, but had never witnessed.
I wasn’t disappointed. The fog’s white mass suddenly parted, two lanes driving through it, each a widening half-cylinder swirling with invisible force, insides darkened by sunrise shadows. The paths dissolved, reclaimed by the mists. However, for that brief moment, I’d actually observed the elusive threat we call wake turbulence.
