After fire, plants are exposed to unshaded environments with little brush competition, and vigorously flower in open environments with increased soil nutrients.
In all, this creates a repeating sequence of four poles, unshaded alternating with shaded, that creates a circumferential traveling field to which the rotor's magnetic poles rapidly synchronize.
Weather conditions in the spotters' high perches are usually to the extreme; unshaded from hot sun, unshielded from high winds (and wind chills), and unprotected from rain.