A colossal winter storm stretching from New Mexico to Maine hit the middle of the United States yesterday with blizzards and freezing rain — and experts said the worst is still to come as it moves northeast.

Wall Street financial markets were operating normally yesterday morning, but officials were making plans for today.

In Washington, the federal government said that workers could take unscheduled leave or telecommute because of the treacherous travel conditions.

The top U.S. airlines United Continental, Delta Air Lines and American Airlines canceled more than 4,000 flights ahead of the storm. Aviation data service Flightaware said more than 6,000 flights have been scrubbed.

The storm is expected to wreak havoc on agricultural operations in the plains states, threatening the dormant winter wheat crop, cattle herds and grain deliveries