A cloud burst is a form of torrential rainfall accompanied by hail and thunder. It is usually observed in high altitude areas and occurs due to the formation of a low pressure area on the top of a mountain. The low pressure zone attracts clouds to the top of the mountain with great force. When they hit the peak, the moisture content is released in the form of rain. The state of Himachal Pradesh witnesses the most number of cloud bursts. Valleys affected by cloud bursts are generally strewn with huge boulders brought down by the rain. Cloud bursts mainly occur in the Himalayas and can cause rainfall of up to 75 mm per hour.