About 50% of all cloud to ground discharges are flashes with more than one stroke. The time interval between the strokes (interstroke interval) is in the range from some milliseconds to some hundreds of milliseconds. Flashes with up to 40 strokes or more can result in a total flash duration exceeding 1 second.

The lightning location system locates each individual stroke separately and groups them to a flash according to a time criterion (all strokes within 1.5 seconds) and a distance criterion (all strokes must be located within a distance of less than 10km from the first stroke).

Statistically, almost every second flash has at least one subsequent stroke. The highest multiplicity of a flash, which was recorded with our LLS up to now, was 32 strokes in a single flash. This flash was striking a radio tower and therefore it was most likely an upward initiated discharge. Upward initiated discharges are known to have a high multiplicity. A comparison of the annual mean multiplicity for negative flashes shows that the mean value decreases from 1998 to 2001. This effect is probably related to the integration into the EUCLID network. The mean negative multiplicity during the years 1998 to 2001 varies between 2.4 and 2.0.

Positive flashes rarely have subsequent strokes as can be seen from the mean multiplicity plot above. Compared to negative flashes almost no positive flashes with a multiplicity greater than 7 are detected. More than 90% of the positive flashes were single stroke flashes.