As an ex-pilot, I will tell you that one of the major causes of death when using an aircraft is flying in poor visibility. We call conditions like that 'Cumulo-

As an ex-pilot, I will tell you that one of the major causes of death when using an aircraft is flying in poor visibility. We call conditions like that 'Cumulo-Granite', otherwise known as 'a cloud with a rock in it'. Fog and cloud are one thing, solid rock and dirt hidden by that fog and cloud are a different thing entirely.