Imagine, for a moment, that the Earth’s atmosphere is simply a big storm-generating engine. Imagine that the ignition trigger for this engine comes in the form of heat rising off the land and ocean surface. And imagine that the engine’s fuel is water vapor evaporated by that heat.

Keep the level of heat and water vapor constant, and you’ll get a continuous, steady stream of storms firing off. But increase the heat and water vapor content, as we have over the past 137 or so years, and the storms that engine produces become a whole hell of a lot more powerful.

In this context, in the last few days record atmospheric and ocean-surface heat helped to produce some of the highest water vapor levels ever recorded over Louisiana. This extreme moisture content, in turn, sparked some of the worst flooding ever seen for the state. From the Pacific Standard: