People skate on an outdoor ice rink in Chicago, the United States, on Jan. 19, 2019. More than 500 flights were canceled at Chicago's two international airports on Saturday as a powerful winter storm hit central and northeastern United States. (Xinhua/Wang Ping)

The iconic sculpture Cloud Gate is covered with snow at Millennium Park in Chicago, the United States, on Jan. 19, 2019. More than 500 flights were canceled at Chicago's two international airports on Saturday as a powerful winter storm hit central and northeastern United States. (Xinhua/Wang Ping)

A man removes snow in downtown Chicago, the United States, on Jan. 19, 2019. More than 500 flights were canceled at Chicago's two international airports on Saturday as a powerful winter storm hit central and northeastern United States. (Xinhua/Wang Ping)

A man removes snow at Federal Plaza in Chicago, the United States, on Jan. 19, 2019. More than 500 flights were canceled at Chicago's two international airports on Saturday as a powerful winter storm hit central and northeastern United States. (Xinhua/Wang Ping)

A man removes snow at Federal Plaza in Chicago, the United States, on Jan. 19, 2019. More than 500 flights were canceled at Chicago's two international airports on Saturday as a powerful winter storm hit central and northeastern United States. (Xinhua/Wang Ping)

A worker drives a snowplow in downtown Chicago, the United States, on Jan. 19, 2019. More than 500 flights were canceled at Chicago's two international airports on Saturday as a powerful winter storm hit central and northeastern United States. (Xinhua/Wang Ping)