The WebEcoist has a gorgeous round-up of beautiful environmental photography. While there are a lot of stunning photos on there, I found these pics from storm-chaser Eric Nguyen incredible. You really get a sense of both the raw, swirling power of the storm, but also how sweeping and beautiful they can be. Of course, what isn't coming through is how inconvenient they often are.
More incredible pics at the WebEcoist.