But in the example of snow retention, evenly spacing both rate-of-fall and rate-of-residence-in-the-clouds values will give different distributions of result.
Mr Cunningham said that sighted pilots needed to be able to fly "blind" through clouds and at night so his challenge was not too different from normal flying.
Meanwhile a team of Swiss researchers are harnessing rays of light for an entirely different purpose -- they've figured out a way to create rain clouds by shooting laser beams into the sky.