What is in news :The  excessive rain and the landslides in Uttarakhand, as well as other states such as Kerala, is linked to the changing patterns of monsoon

Details :

• The extended stay of the monsoon means that the weather systems are still present in the country to create the circumstances for sporadic excess rainfall.
• Western Disturbances, which are present in the country through the year, rise above a certain latitude in February and then descend after October. This is the time the monsoon has retreated from the country, so the conditions, especially in hill states such as J&K, Uttarakhand and Himachal Pradesh from where monsoon retreats the earliest, are dry. So, the Western Disturbances are restricted to causing light winter rainfall from November. This year, however, a combination of Western Disturbances along with the low-pressure system created by the monsoon has led to untimely, excessive rains.
• Low-pressure area travelled all along the Northern Limit of Monsoon (NLM) which was then passing through parts of Central India. The system moved north towards Uttarakhand and then recurved towards Uttar Pradesh.