Strong gale brought by tropical storm Kestana began to hit China's southernmost island province of Hainan on Monday.

Photo taken on Sept. 28, 2009 shows the dark clouds over Qionghai City, south China's Hainan Province. The Chinese central observatory forecasts Kestana, the 16th tropical storm this year, will continue strengthening and would hit southern coastal areas of Hainan or pass through the southern coast of Hainan to lash coastal regions in Vietnam on Tuesday or Wednesday. It ordered boats in Kestana's path to return to harbor. [Meng Zhongde/Xinhua]

The provincial meteorological station monitored the storm at 16.1 degrees north and 113.3 degrees east, and was 470 km away from Hainan on Monday morning.

The station said the storm had strong winds of 108 km an hour at its eye, and is gathering strength. Its northern section may pass through the southern island on Tuesday.

The station on Monday issued a yellow alert on Kestana, under which all outdoor activities should be canceled, maritime affairs departments call vessels to return to harbor, and move coastal residents to safe places.

Kestana, the 16th storm to hit China this year, turned into a strong tropical storm at 5:00 a.m. Sunday, after causing severe casualties in the Philippines.

A girl rides bicycle in rain in Qionghai City, south China's Hainan Province, Sept. 28, 2009. [Meng Zhongde/Xinhua]