"There Is No Reason To Fly Through A Thunderstorm in Peacetime"

That's on a sign over squadron ops desk at Davis-Monthan AFB, in Arizona in 1970. This photograph was actually taken by a storm chaser in 2014. 

Marko Korošec’s apocalyptic photo of a storm cloud near Julesburg, Colorado, was selected as the Grand Prize winner by National Geographic Traveler.  As NGT director of photography Dan Westergren said: “This winning photo of a supercell over the plains of eastern Colorado stopped the judges in our tracks.

“What makes the picture particularly strong is that except for the cloud, the rest of the scene is quite ordinary. The crazy UFO-looking shape gives the impression that it’s going to suck up the landscape like a tablecloth into a vacuum cleaner. The unresolved tension in the image makes me want to look at it over and over.”

Still, it's a good reminder to all pilots to avoid thunderstorms at all costs.