A cold snap hit northwestern Chinese regions Wednesday, bringing chaos, including flight delays, traffic jams and stoppages in power and heat supplies.

Heavy snow blanketed most parts of the Xinjiang Uygur Autonomous Region Tuesday night, bringing down the low temperature to minus 40 degrees Celsius in the north and east of the far western region.

A woman walks in heavy snow in Urumqi, capital of the Xinjiang Uygur Autonomous Region. [China Daily]

In some areas, it packed winds sweeping at up to 100 kilometers per hour, a regional weather bureau spokesman said.

"This is by far the worst cold snap of this winter," he said. "It was a result of chilling factors from western Siberia."

In the Kazak Autonomous Prefecture of Ili, the snow began at 7 p.m. Tuesday and stopped at 2 a.m. and cut off power and heat supplies in Yining, a city of about 430,000 people.

Power resumed Wednesday morning and repair work was continuing to restore the heating system.

More than 200 vehicles were stranded on the zigzagging mountain roads in the Ili River Valley Tuesday night, when the fresh snow measured at least 20 centimeters deep, a traffic policeman said.

The blizzard closed the international airport in Urumqi Wednesday, with thousands of passengers stranded in the terminal building. The snow on the runway measured more than 20 cm at midday.

"The snow hasn't stopped, and it's very hard to clean up on the runway and the aircraft," said Ding Hua, a stranded passenger, by phone.

The Xinjiang branch of China Southern Airlines alone estimated that 90 of its flights would be canceled or postponed Wednesday.

The cold snap also hit the northwestern Shaanxi Province Tuesday and brought down temperature by 10 degrees Celsius, causing a run on gas supplies.

Liu Fengling, a resident in the provincial capital Xi'an, complained she could not light her cooking stove Tuesday night.

Taxi drivers also complained they had to wait hours to fill up their gas tanks over the past week.

A spokesman with Xi'an Qinhua Natural Gas Corp said the city's gas consumption had topped 5 million cubic meters daily, more than three times the normal 1.5 million cubic meters.

He said the sudden freeze had increased demand for gas and his company would consider capping industrial and commercial gas consumption to meet demand.

The National Meteorological Center has warned the cold wave will also affect the three northeastern provinces and north China with Beijing at the center.

It said the average temperature in these regions will drop by eight to 12 degrees Celsius from Wednesday afternoon to Friday.