“Weather events” is a nice way of describing atmospheric phenomenon that wreak havoc on us, directly or indirectly and in varying degrees of severity. The most obviously calamitous examples of these events are cases of winds gone wild — hurricanes, tornadoes, cyclones. These seem particularly insidious because they give physical, visible, destructive shape to something we otherwise hardly notice: the air we breathe.

Hurricanes and cyclones (also called typhoons) are immense, swirling tropical storms that form when hot air rises over warm seas near the equator. Tornadoes, born out of thunderstorms, take shape over land, turning into funnels of spinning air that can cut a path as much as a mile wide across the countryside. Both kinds of event can have catastrophic results, causing massive property damage and claiming lives.

Floods can be massively destructive, too. Water is vital for life — between 55% and 60% of our bodies is made up of it — but it can be deadly when too much of it comes too fast. Floods are often caused by heavy rainfall or rapid snow melt, causing rivers and other bodies of water to overflow. Other causes include incompetent damming that raises water levels and sometimes by earthquakes or major coastal landslides that set off walls of water known as tsunamis.

It might be said that the opposite of floods are droughts — too little water over a long period of time instead of too much all at once. Droughts are more subtle than floods. People don’t even always realize they’re experiencing one until the rainfall statistics come in, or the crops don’t. As the U.S. Geological Survey’s Water Science School puts it, “While it is relatively easy to define what a hurricane or earthquake is, defining a drought is more subjective.”

The term means something different to a farmer than it does to a meteorologist or water manager. But everyone agrees that a drought is a span of unusually dry conditions caused by a shortage of rain or snowfall, and that the results can include famine and devastated landscapes.

Wildfires might not seem like weather events at first, but weather plays a major role in their development, even when they’re actually sparked by careless or malicious human actions. Excessive heat warms and dries the fire’s fuel — trees and underbrush. Wind feeds the fire with oxygen and spreads it quickly from its source. Fire also creates winds of its own, known as fire swirls, similar to tornadoes and capable of sucking up burning logs and embers and tossing them across the countryside.

We’re used to seeing images of weather-borne destruction — inundated fields, houses turned to kindling, vast tracts of charred earth, and worse. In order to truly understand how profoundly weather events affect our world, though, it’s illuminating to compare these scenes of disaster to the same scenes as they were before tragedy hit.

Click here for before and after pictures of the world’s worst weather events.
Click here to see our methodology.