A major salt lake on northwest China's Qinghai-Tibet Plateau has reached its largest size in 42 years, meteorologists said Sunday.

The surface of the salt lake in Hoh Xil National Nature Reserve grew to 161.4 square km in early October, up 9.3 square km from the same time last year, according to Liu Baokang at the Qinghai Institute of Meteorological sciences.

Satellite images of the lake in October 2016 and November of this year show that several small islands in the south and east of the lake have been submerged, and a peninsula at the southeast of the lake has become an island.

Liu said the expansion of the lake is mainly the result of increased rainfall. Precipitation recorded by a meteorological station near the lake from August to October is 10 to 160 percent higher than previous years.

Major lakes in the reserve, including Zhuonai, Qusay and Hoh Xil, are all holding water at historically high levels.

Following a dike breach in 2011, water has flown from Zhuonai Lake and fed into Qusay Lake. The latter's overflow has resulted in swelling of the salt lake downstream.

Sitting 4,600 meters above sea level, the 45,000-square-km Hoh Xil nature reserve is China's largest unpopulated area and is home to wild yaks and the endangered Tibetan antelope.

The lake's expansion increases the risk of damaging wildlife habitats and some nearby transportation facilities, said Wang Hailin of the reserve's management bureau.