Most of the discussion of "what to do outdoors" during lightning suggests that you get inside an appropriately constructed solid shelter. Unfortunately, this does not address situations in the woods far from shelters. Here is some more specific and apparently reasonable information from the Fireline Handbook intended as instructions for wildland firefighters:
http://www.nwcg.gov/pms/pubs/410-1/410-1.pdfNational Wildfire Coordinating Group
Fireline Handbook, pg 19-20 (2004)
Thunderstorm SafetyApproaching thunderstorms may be noted by a sudden reverse in wind direction, a noticeable rise
in wind speed, and a sharp drop in temperature. Rain, hail, and lightning occur only in the mature
stage of a thunderstorm.
Observe the 30/30 rule:a) If you see lightning and
hear thunderclaps within 30 seconds take storm
counter-measures identified below.
b) Do not resume work in exposed areas until 30 minutes
after storm activity has passed.
• Take shelter in a vehicle or building if possible.
• If outdoors, find a low spot away from tall trees, wire fences, utility lines, and other
elevated conductive objects. Make sure the place you pick is not subject to flooding.
• If in the woods, move to an area with shorter trees.
• If only isolated trees are nearby, keep your distance twice the tree height.
• If in open country, crouch low minimizing contact with the ground. You can use a pack
to sit on, but never lay on the ground.
• If you feel your skin tingle or your hair stand on end, immediately crouch low to the ground.
Make yourself the smallest possible target and minimize your contact with the ground.
• Don’t group together.
• Don’t stay on ridgetops, in wide open areas, near ledges or rock outcroppings.
• Don’t operate land line telephones, machinery, or electric motors.
• Don’t handle flammable materials in open containers or metal hand tools.
• Handheld radios and cellular telephones can be used.
The cure for a fallacious argument is a better argument, not the suppression of ideas.
-- Carl Sagan