Re: Specific lightning phenomenon

Lightning kills more than a hundred people a year in the US. If you want to watch the storm, the safest place to be is inside a building or inside a car.

There is an intense Electric Field[1] surrounding any lightning bolt, and this field can cause sparks to leap between nearby conductive objects (such as your body and the wood of the dock.) Where high voltages are involved, wood is a conductor unless it has been baked totally dry.

Now if it was a ground strike, there would also be a huge electric current which spreads outwards in the ground surrounding the lightning. This can cause sparks too, as well as often being lethal to anyone standing on the ground or in bodies of water near the strike. And as the initial lightning "leader" approaches the ground, the electric field can cause any object on the ground to send a spark upwards towards the approaching lightning. Any one of the above could have given you a shock.

Did your lightning connect to the ground? If the "bang" occured at the same time as the flash, it probably was a nearby ground strike, and you might have been in the fringes of the high-current region. If so, are lucky to be alive, since the strike could easily have been much closer.

Check out my article describing what lightning might look like if it was very slow.

Here's an excellent book:
ALL ABOUT LIGHTNING, Dr. Martin Uman, Dover 1986
ISBN: 048625237X

Lightning FAQ from the Canadian Forest Service

Lightning page (Yahoo.com)

[1] We all hear about Magnetic fields in early grades in school, yet Electric fields are not mentioned. They get hidden within "static electricity" discussions. But an Electric field is not "static electricity", any more than a magnetic field is made of iron. Rub a balloon on your arm, and you can use your arm-hair to "feel" the invisible Electric field which surrounds the balloon. Stronger electric fields can cause sparks.