The region receives heavy rain in plains and light snow on Himalayas precipitation through two primary weather patterns: the Indian Monsoon and the Western Disturbances. The Monsoon carries moisture northwards from the Indian Ocean, occurs in late summer and is important to the Kharif or autumn harvest. Western Disturbances, on the other hand, are an extratropical weather phenomenon that carry moisture eastwards from the Mediterranean Sea, the Caspian Sea and the Atlantic Ocean. They primarily occur during the winter season and are critically important for the Rabi or spring harvest, which includes the main staple over much of North India, wheat. The states of Jammu and Kashmir, Himachal Pradesh and Uttarakhand receive some snowfall in winter months.