A quote from the article below:
...DURHAM, N.C. -- Duke University engineers have led the most detailed analyses of links between some lightning events and mysterious gamma ray emissions that emanate from earth's own atmosphere. Their study suggests that this gamma radiation fountains upward from starting points surprisingly low in thunderclouds. Counter-intuitively, these strong gamma outbursts also seem to precede associated lightning discharges by a split second....
http://www.spaceref.com/news/viewpr.html?pid=16795
---Al
