The National Marine Environmental Forecasting Centre said ice covers about seven sea miles in the bay, which is the earliest date that sea ice appeared in the area in 10 years.
    
The acreage of sea ice in Bohai Sea will rise to 10 to 12 sea miles with an average thickness of 5 centimetres in the following week due to dropping temperatures.
    
Ice also covered the shallow estuaries in the north of the Yellow Sea, also the earliest in 10 years.
The centre asked departments along the coasts of Bohai and north Yellow Sea to take precautions against damage to ships and facilities.
    
It also forecast huge waves in the East China Sea, around the disputed Islands, the Taiwan Strait and northeast part of South China Sea from tonight and issued a blue alert.

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