[Physics] Why is lightning more rare during snow storms than rain storms

atmospheric sciencelightningwaterweather

Lightning and thunder during a snow storm is uncommon. As far as I know, more uncommon than during a typical rain storm. Why is this? I speculate it might be one, or both, of the following two ideas, one having to do with a change in the dielectric, the other having to do with a change in the catalyst.

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I can't point to a definitive reference, but my recollection is that thunderstorms are associated with a lower layer of warm air rising rapidly through an upper layer of cold air. It's the rapid vertical transport that generates the static charge and hence the lightening. In winter it's rare to get these atmospheric conditions.

So it's not that there's something special about snow that stops lightening, it's that the atmospheric conditions in very cold weather aren't conducive (no pun intended :-) to lightening.

Why your method won't work without sensitive equipment.

The phenomenon you are trying to use to calculate the distance to the source is called dispersion. This is the general term used when waves of different frequencies propagate at different speeds in a medium. Unfortunately, the dispersion of air, particularly at the low frequencies associated with thunder, is very low. The sound speed in air is a relatively constant $343\tfrac{m}{s}=0.21\tfrac{mi}{s}$.
Even if the dispersion were relatively high, you would need to know something about the way the thunder sounded when it started. This isn't a strong limitation as you would probably be able to pick up on it by listening for closer and farther thunder claps.

What relatively simple method will work?

A trick I learned as a child (perhaps you did too) is to count down the seconds between the lightning flash and the thunder clap. From this you can calculate roughly how far away the lightning was. Since the speed of light is so fast as to be considered instantaneous in this situation, the time it took the sound to get to you tells you how far away the lightning struck. If the time for the sound to reach you is $\Delta t$, then the lightning was a distance $$d=\Delta t*v$$ away, where $v=0.21\tfrac{mi}{s}$ is the speed of sound in air. As an example, if you count $5\ \text{seconds}$ for the sound to reach you, then the lightning would be roughly $1\ \text{mile}$ away. You can remember to simply divide by $5$ as a rule of thumb. This calculation gives the distance to the source of the thunder which may be a couple of miles above the ground.

[Physics] Lightning Conductor Working

The lightning conductor provides a very low resistance path between the top of the lightning conductor rod via a substantial strip of metal to the ground so that the current as a result of a lightning strike does not flow through the building to which it is attached.

However that is not the end of the story in that the electrical length of the lightning conductor rod can be thought of a being larger than its physical length.
A large electric field will make air become a conductor and the electric field around sharp objects is larger than that where the surface is flatter.
Around the top of a pointed lightning conductor rod charges are induced by the charge on the clouds above.
When the induced charge is sufficiently large the air around the point of the lightning conductor becomes conducting thus extending the effective length of the conducting path of the lightning conductor.
Modern lightning conductor rods are now made with slightly rounded points because it has been found that although the electric field produced by a charged rounded point as compared with a changed sharp point is smaller the region over which the air is a conductor is larger. So air is conducting over a larger distance above the lightning conductor rod.

Of course the ionisation of the air around a lightning conductor rod increases the chances of lightning striking the rod but that is considered to be safer to have the lightning conductor rod than just allowing the lightning strike in a more random fashion.

There is another benefit of the lightning conductor rod in that in making the air around it a conductor it can thus contribute to the discharge of the clouds without lightning being produced and so reduce the chances of a lightning strike..

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Related Solutions

[Physics] Without seeing the lightning, can you tell how far away it struck by how the thunder sounds

Why your method won't work without sensitive equipment.

What relatively simple method will work?

[Physics] Lightning Conductor Working

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