Archive for August, 2011

Bolt from the Blue

Posted on: August 14th, 2011 by Jonathan Merage 1 Comment

Cloud-to-Ground Superbolt

On the night of the 3rd, I had the rare luck of capturing a less frequently photographed form of lightning called a bolt from the blue.

Such super-bolts, while spectacular to witness and document, are absolutely lethal and destructive as they possess about 10X the charge of the more common negative bolt. Also referred to as dry lightning, they have caused many fatalities and millions of dollars in damage.

The visible lightning discharge (return stroke) originates within the storm’s upper glaciated anvil which holds solid hydrometeors (ice crystals & hail/graupel) that carry positive charge.

The initial stepped leader sets off as an intracloud bolt within the positively charged upper anvil/tower region before traveling outward up to several miles then down towards an unsuspecting target on the negatively charged ground. Positive bolts are the most highly charged and long-lasting form of lightning. While the average common negative bolt carries enough energy to light a 10-watt bulb for 2 months, a positive bolt can release enough energy to light a 100-watt bulb for almost a century!

(see http://en.wikipedia.org/wiki/High_voltage#Lightning”)

Lightning strikes of this kind are surpassed in rarity only by ball lightning, which I personally have yet to witness.

Captured with Canon 40D in northeast Colorado. Exposure time: 23 sec., ISO 100, Canon EF-S 10-22mm zoom.