Weather Wise Kids Question: I’m Lanning… a 5th grader at Charles Ellis. My question for Mr. Haywood is why does lightning only happen when it rains?
Lanning… it takes the right conditions for lightning to develop. And it almost always happens inside a cloud.
Within a cloud… ice bump into each other as they move around. All those collisions create an electric charge.
Eventually the whole cloud fills up with electrical charge. The positive charges form at the top and the negative charges form at the bottom.
If a positive charge builds up on the ground beneath the cloud… around anything that sticks up… such as mountains… people or single trees… then the charge coming up from these points eventually connects with a charge reaching down from the cloud… and you get a lightning strike.
So as you can see… the cloud is creating the lightning.
These clouds usually produce rain which can reach the ground… but not always.
Sometimes out west… dry thunderstorms develop. this refers to thunder and lightning that occur without rain falling to the ground. The rain droplets simply evaporate in the air before reaching the ground.
Also… it is possible that you might see lightning and not see rain because it is too far away. Sometimes this is called “heat lightning”.
And one unusual example… some volcanic eruptions on rare occasions produce lightning. Instead of ice particles… dust from the eruption create the static charge for this to occur.