China upgrades alert against typhoon Krosa

China's National Marine Environmental Forecasting Center (NMC)on Saturday upgraded its wave warning from yellow level to orange as Typhoon Krosa strengthened to a strong typhoon on Friday night, said Chinese news agency (Xinhua). Krosa, the 29th typhoon of the year, will bring waves as high as nine meters in the northern part of the South China Sea from Saturday noon till Sunday noon, the center said. Saturday morning, the typhoon center was at the northern part of the South China Sea and about 605 kilometers east of the city of Wanning in southern China's Hainan Province. The NMC forecast that it will move westward at a speed of 10 to 15 km per hour towards Hainan as its force slowly weakens, urging local governments to take precautions against the typhoon while ships in areas on the route of Krosa should come back to ports. China has a four-tier, color-coded weather warning system, with red representing the most severe, followed by orange, yellow and blue.