on Hurd Peninsula. The principal mountain formations on the island comprise Tangra Mountains ( long and wide, with Mt Friesland rising to ), Bowles Ridge ( long, elevation ), Vidin Heights (, ), Burdick Ridge (), Melnik Ridge () and Pliska Ridge () in the eastern part of the island, and Oryahovo Heights (, ), and Dospey Heights (, ). The local ice relief is prone to change; in December 2016 the elevations of Mount Friesland and St. Boris Peak were and respectively, making the latter the summit of Livingston in that season. According to the American high accuracy Reference Elevation Model of Antarctica (REMA), Mount Friesland is higher than St. Boris Peak. The first ascent of the island's summit Mount Friesland was made by the Catalans Francesc Sàbat and Jorge Enrique from Juan Carlos I Base on 30 December 1991. Of the other notable peaks of Tangra Mountains, Lyaskovets () was first summited by the Bulgarians Lyubomir Ivanov and Doychin Vasilev from Camp Academia on 14 December 2004, Great Needle Peak (Falsa Aguja Peak, ) – by the Bulgarians Doychin Boyanov, Nikolay Petkov and Aleksander Shopov from Camp Academia on 8 January 2015, St. Boris – by Boyanov and Petkov from Camp Academia on 22 December 2016, and Simeon () – by Boyanov, Petkov and Nedelcho Hazarbasanov from Nesebar Gap on 15 January 2017. Of the island's nature, Captain Robert Fildes of the sealers and (both of them shipwrecked in the South Shetlands) wrote in 1821: Climate The climate of Livingston is polar tundra under the Köppen-Geiger climate classification system. Climatic conditions are influenced by the following specific factors: the island's location in the narrowest part of the Southern Ocean (less than 600 km between the Antarctic Convergence and the Antarctic Peninsula); the relatively small amplitude of water temperatures in the surrounding sea; the local relief including Tangra Mountains, one of the highest mountain ranges in the archipelago that contributes to shaping the local atmospheric circulation; and the ice cap of the island. Surface air temperature decreases with increasing altitudes, which in the interior of eastern Livingston Island reach 550 m at the centrally located Wörner Gap and over 1400 m at the crest of Tangra Mountains. The local variety of the Antarctic Peninsula weather is particularly changeable, windy, humid and sunless. Says Australian mountaineer Damien Gildea who climbed in the area: ‘Livingston got just about the worst weather