Today marks Qingming Festival -- or tomb sweeping day -- a traditional Chinese holiday during which people pay respects to their ancestors and remember those who've passed away.

The weather typically is pleasant during the holiday, but instead this year China is seeing a cold snap. Beijing on Wednesday issued a blue snowstorm alert -- the lowest of a four-tier system. The capital saw April snow for the first time in thirty years. In north China's Shanxi Province, temperatures dropped by up to twenty degrees Celsius, and northwestern Gansu Province saw sandstorms. The extreme weather is expected to last until Saturday. Authorities have urged people to take precaution.