There were reports of various winter expeditions in the Himalayas, including K2, Nanga Parbat, and Meru with the buzz for the Everest 2019 beginning just 14 weeks to the weather window. Noted climber Cory Richards announced on Twitter that he was hoping to establish a new climbing route to the summit in 2019. Also announced was an expedition to re-measure the height of Everest, particularly in light of the 2015 earthquakes. China closed the base-camp to those without climbing permits in February 2019 on the northern side of Mount Everest. By early April, climbing teams from around the world were arriving for the 2019 spring climbing season. Among the teams was a scientific expedition with a planned study of pollution, and how things like snow and vegetation influence the availability of food and water in the region. In the 2019 spring mountaineering season, there were roughly 40 teams with almost 400 climbers and several hundred guides attempting to summit on the Nepali side. Nepal issued 381 climbing permits for 2019. For the northern routes in Chinese Tibet, several hundred more permits were issued for climbing by authorities there.