Cloudbursts are caused when updrafts fail. These updrafts contain massive amounts of water vapor traveling at high speeds so that when it fails, heavy rainfall results, which is a cloudburst.
Updrafts fail, resulting in cloudbursts for a number of reasons. One reason is that heat energy mingles with the water vapor. Sometimes cloudbursts result when clouds heavy with water vapor collide with a mountain.
Cloudbursts are intense but do not last long, which can create flash floods, according to the Chicago Tribune. This is especially dangerous in hilly terrain. India has a long history of cloudbursts and the ensuing disaster. For instance, in 1908, a cloudburst caused the Musi River to flood, killing 15,000 people. An entire village was destroyed because of a cloudburst in 1970. In 1998, a cloudburst caused a landslide in Malp that killed hundreds of peoples. In 2005, a cloudburst swelled a river by 37 inches in just a few hours, killing more than a thousand people in Mumbai. The Times of India reports that the instances of cloudbursts at Himachal Pradesh are increasing drastically. The danger lies in the region's 249 glacial lakes and the devastation that would commence if those lakes were to be breached because of rapidly rising waters from cloudbursts.