When it rains and thunders, people's hair will stand up and be struck by lightning. Why are they close to the ground? Is it on the ground?

Hair standing up means that the earth's charge has been concentrated on your hair, because there are charged clouds in the sky. It may break through the air at any time and discharge on your head. This is lightning strike.

The tips are easy to discharge, because the distance between the tips is short, the breakdown impedance is small, and it is easy to discharge, that is, to be struck by lightning. So come down, not in the open air.