China has maintained its blue alert for intense snowfall in the central parts of the country, which has so far killed 13 people, the National Meteorological Centre said on Saturday.The NMC issued a blue snowstorm alert, the least severe of its four-tiered alert system after red, orange and yellow, for both Saturday and Sunday.The agency said it expected blizzards to dump 4 to 8 centimetres of snow in parts of Shaanxi, Shanxi, Henan, Anhui and Hubei provinces and some areas could be hit with more than 10 centimetres, Xinhua news agency reported.The NMC warned residents of the affected areas to stay indoors and asked authorities to take precautionary measures for roads, highways and electric and telecommunication systems.The first snow of 2018 affected large parts of northwestern, central and eastern China since Wednesday, killing at least 13 people and damaging houses, agriculture and power facilities, according to local authorities.The affected area was spread over 13,100 hectares of farmland, out of which more than 900 hectares had been destroyed, causing an estimated loss of $78.6 million.