<P> For much of Himalayas--that on the south side of the high mountains, except in the furthest west, the most characteristic feature of the climate is the monsoon . Heavy rain arrives on the south - west monsoon in June and persists until September . The monsoon can seriously impact transport and cause major landslides . It restricts tourism--the trekking and mountaineering season is limited to either before the monsoon in April / May or after the monsoon in October / November (autumn). In Nepal and Sikkim, there are often considered to be five seasons: summer, monsoon, autumn (or post-monsoon), winter and spring . </P> <P> Using the Köppen climate classification, the lower elevations of the Himalayas, reaching in mid elevations in central Nepal (including the Kathmandu valley), are classified as Cwa, Humid subtropical climate with dry winters . Higher up, most of the Himalayas have a subtropical highland climate (Cwb). </P> <P> In the furthest west of the Himalayas, in the west of the Kashmir valley and the Indus valley, the South Asian monsoon is no longer a dominant factor and most precipitation falls in the spring . Srinagar receives around 723 millimetres (28 in) around half the rainfall of locations such as Shimla and Kathmandu, with the wettest months being March and April . </P> <P> The northern side of the Himalayas, also known as the Tibetan Himalaya, is dry, cold and generally wind swept particularly in the west where it has a cold desert climate . The vegetation is sparse and stunted and the winters are severely cold . Most of the precipitation in the region is in the form of snow during late winter and spring months . </P>

Name the important rivers that originate beyond the himalayas