Bolt From the Blue

This image depicts a lightning phenomenon known as a “bolt from the blue” with a small jet of lightning forming in the upper cloud area. Most people see lightning strikes that go from clouds to the ground, but some lightning goes upward, forming blue jets and gigantic jets. Perhaps the most dangerous lightning appears as "bolts from the blue" – lightning that begins upward, but then moves sideways and then downward to hit the ground as much as three miles from a thunderstorm.

The mechanism behind different types of lightning may now be understood, thanks to a combination of direct observation and computer modeling reported by a team of researchers from New Mexico Tech and Penn State. The bolts develop like normal intracloud lightning before escaping the thundercloud at upper levels and branching toward the ground. The researchers also discovered that upward and sideward lightning events occurred shortly after normal downward lightning bolts occurred or after intracloud lightning produced a local charge imbalance in the cloud.

Credit: Harald E. Edens,New Mexico Tech