Thunder waves?

[divingmoose]

This week end in Westhawk lake in Manitoba I was standing on the shore watching
a storm coming toward us from the north, there was no wind to speak of, no waves.There was a large very load crack of thunder and a few seconds later there were waves on the lake??? I did look around figuring first it was wake from a boat !no boat traffic on the lake.
Anybody seen anything like this? any Ideas !
A little Lake info: Meteor Crater lake in Mostly Granite bedrock 360 ft max depth surface temp 71 F tremocline 30 FT 62f

 

[super7]

From what I remember,,,
Electric discharge between the thundercloud and earth creates a band of plasma
(this being the lightning bolt), which expands extremely fast. The speed of expansion
exceeds the speed of sound, creating a shock wave (thunder).

I speculate that the waves you saw was a result of either this shockwave hitting the lake surface, or the lightning hitting the lake and shockwaves forming within the lake itself.

Good thing you didn't get hit or shocked by lightning!

 

[Ketos]

Thats a pretty incredible story. I wish i could say i've seen that before. As for your question to it being possible, it is very likely that the storm caused those waves.
I'm sure you've felt thunder in your body after a loud crack before. Same thing happened with the water.

Another cool phenomenon that i discovered this summer was hearing the anchor chain rattle through the rope down on the wreck. On a calm day you can hear the chain through 100' of rope on the surface, its pretty eerie. haha

 

[Charlie99]

Another cool phenomenon that i discovered this summer was hearing the anchor chain rattle through the rope down on the wreck. On a calm day you can hear the chain through 100' of rope on the surface, its pretty eerie. haha

Tie off the rope to a big flat piece of metal and you'll have one end of a oversized "tin can and string telephone" setup.

 

[ClayJar]

This week end in Westhawk lake in Manitoba I was standing on the shore watching
a storm coming toward us from the north, there was no wind to speak of, no waves.There was a large very load crack of thunder and a few seconds later there were waves on the lake??? I did look around figuring first it was wake from a boat !no boat traffic on the lake.

I would find it highly implausible that thunder would be the cause of waves on a lake. For one, as a compression wave in air, thunder just doesn't have the oomph to put into waves. There's also the extreme disparity in wave velocities when you compare water waves and thunder. At its slowest, thunder moves at the speed of sound, which means it is long gone before having much chance at all to stir up waves.

Boats make good waves because they apply sufficient brute force to shove enough water around to form the wave. A light breeze can make good waves because it just keeps pushing lightly. (Think of those big marble balls you sometimes see at museums. They may weigh a ton, but if you just keep gently pushing them in one direction, you can get them spinning at a rather exciting clip.) Thunder has neither the energy to brute force a wave into existence nor the duration of effect necessary to coax waves up.

Did you note how long it was between flash and bang for the thunder? (The "about 5 seconds per mile" rule of thumb would provide a rough estimate of distance, which could rule out some possibilities.) What did the waves look like (size and period)? It would seem most likely that they were caused by something not in your local observable vicinity. As West Hawk Lake is around 2-2.5 miles (about 3-4 kilometers) across, it seems quite plausible that the waves were perfectly normal without you observing the cause. Perhaps the wind just didn't reach you.

(One fun possibility would be waves caused by a steam explosion when lightning was discharged into the water. I'm not sure what conditions would be required for something like that, but it'd be fun to investigate.)

 

[Pug211]

Steam Explosion? Hadn't thought about that, the lightning would have to ground out to create the heat, but if it could do that, this is not out of the question.

 

[divingmoose]

clay jar: I like the idea of the steam explosion causing the wave. the thunder clap and the wave were only a few seconds apart and if a steam explosion is the likely suspect Im going with it. normally the wake/waves from a boat roll large to small then disapate.The waves I seen were like wash board maybe 6 inches-1 ft apart and only about 4-8 inches high 20 or so waves and that was it only lasted afew seconds themselves. more like a vibration or a tremer than waves (no earth quakes around here)