Authorities have prohibited trekking on routes above 4,000 metres in reserved forest areas of Uttarkashi district, including the popular Gaumukh-Tapovan trail in Gangotri National Park, following heavy snowfall in the higher Himalayan reaches. UTTARKASHI: Authorities have prohibited trekking on routes above 4,000 metres in reserved forest areas of Uttarkashi district, including the popular Gaumukh-Tapovan trail in Gangotri National.