The ongoing eruption of Icelandic volcano Eyjafjallajökull has filled the atmosphere with so much dust that airplanes throughout the world are grounded. These incredible photographs show the lightning-laced wrath of the volcano that won't stop.
Volcanic clouds are often full of lightning, though the process that causes it is not well understood. (Here's a great article from IEEE on current theories, though). Dust from Eyjafjallajökull is keeping planes out of the air because the ash from the eruption is laced with shards of glass so fine that they can gum up jet engines and cause catastrophic failures.