People ride during a snowfall in Mudanjiang, northeast China's Heilongjiang Province, Nov. 13, 2010. The National Meteorological Center issued the blue alert for snowstorms on a second consecutive day as heavy snowfalls hit southern and eastern Heilongjiang and neighboring Jilin Province in the east on Saturday. China has a four-color snow warning system: red, orange, yellow and blue. Blue is the least serious level. (Xinhua/Zhang Chunxiang)