The Power of Positive Lightning

Airplanes are built to withstand bolts of lightning, because strikes on planes happen now and again. But in 1999, a glider soaring above Dunstable, England, was struck by a bolt out of the blue -literally, because the plane was not in a storm- which ripped the craft apart at the seams, including peeling apart the laminated layers of its surface.

Suspicion rapidly settled on the phenomenon known as ‘positive lightning’. Awareness of positive lightning’s significance has gradually increased in recent decades, and it is now believed to comprise up to 5% of all lightning strikes. The negative charge at a storm cell’s base is balanced by a strong positive charge at the cloud’s anvil-shaped top, up to 60,000 feet above the ground. While there is also a positive charge on the ground immediately underneath the storm cell, significant charge differentials can develop between cloud tops and negatively-charged land surfaces much further away. Occasionally these differentials are sufficient to spark a positively charged lightning strike— a huge high-energy arc capable of hitting the ground more than ten miles from the storm itself, often under clear skies and bright sunshine.
Vast energies are required to deliver these bolts from the blue. Research suggests that positive lightning can generate currents and potentials ten times greater than negative strikes: up to 300,000 amps and 1 billion volts, or approximately 300,000.21 gigawatts of power in a single discharge.

But what happened to the glider and the two men inside? Find out at Damn Interesting.