Lightning and related phenomena in thunderstorms and squall lines

During the past few years, cooperative research on storm electricity has yielded the following results of both basic and applied interest: (1) the intracloud to cloud-to-ground flashing ratio can be as great as 40:1; (2) as storm cells in a squall line dissipate, longer flashes become predominant; (3) there are two centers of lightning activity maxima that are vertically separated, the lower maximum at about 5 km and the upper at about 12 km. In addition, (4) storms produce lightning in their upper regions at a high rate; (5) lightning appears to be related in time to convective motions; (6) positive cloud-to-ground flashes occur in the severe stage of storms and in the later, well-developed stage of squall line storms; (7) mesoscale convective complexes have been observed to have cloud-to-ground flashing rates of more than 48/min; and (8) the electric field in anvils well away from the main storm core (more than 60 km) can be very high, more than 94 kV/m.