What is the cause of the present disaster in Pakistan?

The current horrible wave of floods and landslides triggered by torrential monsoon rains has killed more than 900 people in Pakistan while 1 million people have become homeless as the flood is now hitting Western and Southern parts of the country, local media reported on Saturday. At least 342 people have been injured, while thousands of others are still missing as non-stop horrible monsoon rains, flash floods and land sliding brought disaster in the northwestern province Khyber Pakhtunkhwa (KP). Flood has cut off the province from the other part of the country destroying all link-roads.