Eric,

Great question.  During winter months in Colorado, I rarely unplug and
ground my antennas.  However, I have seend, or heard rather, snow thunder
and it is common in about February.  Those bolts of snow lightning can be
just as deadly as summer storms.  My antenna was hit by lighting a few years
ago.  Well, that antenna didn't survive, of course, but I now make it a
habit never to leave my gear connected when I'm not on the air during the
warmer months.  I'll be interested to hear what the guys and gals in the
real lightning states have to say.  You know, places like Oklahoma, Kansas,
Texas and a few others.  They claim that lightning can be as far as 20 miles
in front of an approaching storm.  In fact, when my antenna was hit at 65
feet, it was a dry storm for 15 minutes before a single drop of rain fell.
Yet lightning was striking all over this area of western Denver.

Phil.
K0NX