One of my favorite sounds in the summer is the slow passage of a distant thunderstorm, with quiet conditions locally allowing the enjoyment of 'gentle' thunder, rolling along for perhaps ten or fifteen seconds after the initial onset.
I have never seen a good explanation for how the length of time that a distance lightning discharge creates a longer rolling sound. Is it cloud to cloud lightning discharging towards and away from me, rather than perpendicular?
I have a hard time thinking the sound is reflected from clouds and rain internal to the clouds, and the lightning is usually far enough away that a flash isn't seen, nor the usual sharp start to the thunder that occurs with closer strikes.
Anyone know why, or heard a good explanation?
One last observation and again a question as to the mechanism. Forgive my prose, my grammar school teacher didn't advise me to go into creative writing.
To set the stage, at maybe two or three a.m. I was awakened by the sound of distant rolling thunder coming through our open bedroom window. I love the sound, and get to hear it so seldom with quiet local conditions and no wind or rain in the trees, that I stayed awake listening to it rather than fall back to sleep.
I used the '1001, 1002, 1003...' method of trying to time the length of each roll, knowing that the perception of time can be warped with being tired or not having some more precise way of gauging the time I could hear the rolls.
Most were in the 10 - 12 second range.
Then, a very rare occurrence of a wonderful roll: It started as the others did, but according to my counting, persisted for 35-37 seconds. During the roll, at about 15 seconds, it became somewhat louder and as it decreased in intensity at about 20 seconds, the vibration must have hit a resonance of the house and ground, since the whole house 'shuddered' and I perceived a true shake or movement of the house as would be from a very nearby strike with more acoustic energy in it. No dishes nor windows rattled, but it definitely gave a good shake for a couple seconds, then the roll continued to die out.
A few more normal rolls, then the same longer roll, with the ground/house shake or resonance occurred again. Very cool.
I am at a loss to explain the longer rolls, and wonder if anyone else has experienced the resonance or shaking of a building from thunder who's original lightning must have been 15-20 miles distant?
Thoughts?
Whatever caused it, it was wonderful and no I hadn't been drinking or smoking anything.
