positive flash (lightning)

A positive flash is a lightning discharge which brings positive charge to ground in the stepped or dart leader. Comprising only 4 percent of all lightning flashes detected annually, the median return-stroke peak current is 45 kiloamperes (15 kiloamperes larger than for a negative flash). A positive flash usually has only one return stroke but that stroke is responsible for 100 coulombs or more of charge transfer. It is known to be one cause for forest fires.