An “anomalous” triggered lightning flash in Florida
Article first published online: 25 APR 2013
©2013. American Geophysical Union. All Rights Reserved.
Journal of Geophysical Research: Atmospheres
Volume 118, Issue 8, pages 3402–3414, 27 April 2013
How to Cite
2013), An “anomalous” triggered lightning flash in Florida, J. Geophys. Res. Atmos., 118, 3402–3414, doi:10.1002/jgrd.50261., , , , , , and (
- Issue published online: 22 MAY 2013
- Article first published online: 25 APR 2013
- Accepted manuscript online: 22 FEB 2013 01:33PM EST
- Manuscript Accepted: 8 FEB 2013
- Manuscript Revised: 31 JAN 2013
- Manuscript Received: 13 DEC 2012
- DARPA NIMBUS. Grant Number: HR0011-1-10-1-0061
- NASA. Grant Number: NNK12EA79P
 An “anomalous” rocket-and-wire triggered lightning flash, a flash whose leaders do not follow the triggering wire remnants to ground, is characterized via high-speed video images at 10 and 300 kilo-frames per second, still camera images, 66–72 MHz source locations from a Lightning Mapping Array, channel-base current, and electric field and electric field derivative (dE/dt) measurements. This is the first anomalous flash of about 410 classically triggered flashes in north-central Florida. The flash began with an upward positively charged leader (UPL) initiating from the tip of the upward-moving triggering wire about 280 m above ground level. All but the bottom 17 m of wire exploded (became luminous) 37.6 ms after UPL initiation. A stepped leader initiated, likely from the top of the wire remnants, 282 m above ground level about 1.3 ms after the wire explosion and propagated downward for 2.1 ms, attaching to the top of a grounded utility pole 117 m southwest of the launching facility. The line charge density on the stepped leader is estimated to be of the order of 10−3 C m−1. Contrary to previously reported “anomalous” flashes in France and New Mexico (roughly 16% and 31%, respectively, of their triggered flashes), in our event, there was not a tens of milliseconds current-zero period preceding the stepped leader, there was no observed downward dart leader in the UPL channel prior to the stepped leader to ground, and there was a failed attempt to reestablish current in the exploded-wire channel between the UPL and ground.