SHENYANG -- Following two days of red alerts for blizzards, meteorological authorities in Northeast China's Liaoning province on Monday lowered the blizzard alert to orange.

The provincial meteorological center said snowstorms are likely to continue until 8 pm Tuesday.

The Taoxian International Airport in the provincial capital of Shenyang closed from Sunday midnight to 10 am Monday.

As of Monday, the airport has carried out de-icing operations on the runway, taxiway and apron. It gave the green light to six outbound flights while canceling all incoming flights on Monday.

All expressway toll stations in the province remain closed as of Monday.

The provincial transport department has mobilized forces to remove snow on expressways. As of 8 a.m. Monday, 1,730 people assisted with 752 sets of machinery and equipment joined around-the-clock work.

In addition to road and airport closures, the heavy snow caused the roofs of many greenhouses for growing vegetables and raising pigs in Shenyang to collapse.

China has a four-tier color-coded weather warning system for snowstorms with red representing the most severe, followed by orange, yellow and blue.

China's National Meteorological Center on Sunday continued to issue an orange alert for snowstorms in the northern regions. Snowstorms were forecast to hit parts of Inner Mongolia, Hebei, Tianjin, Shandong, Liaoning, Jilin and Heilongjiang until the wee hours of Monday.

In Changchun, the capital city of Jilin Province neighboring Liaoning, authorities closed schools and kindergartens on Monday as heavy snow and icy rain made roads slippery. The city's metro system was shut down due to the adverse weather.

The airport in Harbin, capital of China's northernmost province of Heilongjiang, was closed from 9 am Monday due to ice on the runway. The airport authority said it would remain closed until Tuesday noon.

The airport authority has deployed forces to clear the runway and helped stranded passengers change schedules.