Thunder and lightning have been occurring in nights as there has been little rainfall during the day, added the spokesperson, which has caused the land surface to heat up. ``This further leads to low level convergence of air due to its circulation in a limited area and gives rise to instability in the atmosphere,'' he said. Violent thunderstorms have also occurred in parts of Gujarat and Uttar Pradesh. Such weather conditions cause two types of clouds: `cumulus clouds' and `cumulonimbusclouds', which are mainly responsible for the natural `laser show' of thunder and lightning. The electric charge is reportedly so great in these low level clouds that lightning has a vertical extent of seven to 12 kilometres, occasionally hitting land to cause fatal injuries. On Friday alone, over a dozen persons were struck by lightning in the city, and two even died due to bolts from the blue. Eight deaths have been reported due to heavy rains in the state,and the death toll since the beginning of the monsoon has touched 102.

However, people staying in high-rise apartments need not particularly worry, as such buildings are well generally insulated from lightning by earthing. In fact, a resident of Maker Towers, Cuffe Parade, even called up to say: ``The thunder and lightning on Friday and Sunday was the most beautiful natural spectacle... Something like an action packed Star Wars thriller on a special 100 mm screen, with terrific acoustics! It also felt like the National Geographic channel had shiftedfrom the small screen to Mumbai's skyline for a while to entertain the masses!''