Landslides are the most catastrophic natural disaster that risks hilly people’s lives and significantly affects economic loss worldwide. A significant landslide occurs yearly in the Chamoli district of the Uttarakhand state’s Indian Himalayan area. The majority of landslides in this area, according to the landslide inventory dataset, are caused by prolonged periods of heavy rain. For this reason, it becomes necessary to find out the rainfall threshold. In this research, we define the empirical rainfall threshold for the possible commencement of a landslide using the information on 200 landslide points in the Chamoli district. In the intensity-duration plot, the threshold rainfall condition for the antecedent precipitation for 3, 5, 10, and 15 days is I = 0.667 D0.7947, I = 4.979 D0.296, I = 6.34 D0.196, and I = 2.493 D0.366 respectively, where I = rainfall intensity (in mm/day) and D = Rainfall duration (in days). It is seen that for 10 days minimum of 7.687 mm of rainfall is required and for 15 days 3.593 mm of rainfall is required to trigger landslides. It is suggested that with the increased number of landslide days, the chances of landslides are shifted toward antecedent precipitation. The derived intensity duration equation can be used for the landslide warning in this region to reduce the risk influenced by this phenomenon.