BEIJING, Feb. 14 (Xinhua) -- Snow fell in Beijing again on Thursday after the first snow of this winter hit the city on Tuesday.

The snow started at about 5 a.m. from the western and northern mountain areas, and gradually reached most parts of the city. It is expected to last until Thursday night, with a maximum precipitation of 4 mm in the western and northern mountain areas, and an average precipitation of 1 mm in downtown areas, according to the Beijing meteorological bureau.

The bureau has issued an alert for icy roads as of this morning.

More than one hundred bus lines were affected, and flights have been delayed and canceled at Beijing International Airport due to the snow.

According to the National Meteorological Center, north China is experiencing this winter's largest and heaviest snow on Thursday, with estimated accumulations of as much as 2.5 centimeters.