BEIJING, July 18 (Xinhua) -- China's marine environmental authority on Friday issued red alerts against dangerous storm tides and sea waves expected to be generated by super typhoon Rammasun in south China.
By about 5 a.m. Friday, Rammasun had strengthened to a super typhoon, packing rainstorms and winds of up to 180 km per hour, said the alert issued by the National Marine Environmental Forecasting Center (NMEFC).
The typhoon is moving northwest at a speed of 20 to 25 km per hour and is expected to make landfall in coastal areas of south China's island province of Hainan and Guangdong Province from Friday afternoon to night, according to the NMEFC.
It may be the strongest typhoon witnessed in the two provinces for a decade, it added.
Coastal areas in western Guangdong have already experienced storm surges from 20 to 80 cm and the NMEFC forecasted that the maximum surge in such areas may reach six meters.
The center also warned that the typhoon may whip up sea waves of more than 10 meters.
The northern part of South China Sea may see waves of up to 13 meters, and in western Guangdong and eastern Hainan, five to seven meters, it said, adding that western Hainan and coastal areas in Guangxi may also witness waves as high as four meters.
The center has told local residents and travelers in these regions to keep away from the dangerous coastal areas.
China uses a four-tier color-coded weather warning system, with red representing the most severe alert, followed by orange, yellow and blue.