Weekend of wacky weather as strong winds, sand, snow and rain hit nation

Gale-force winds that have battered northern China swept into the southern parts of the country over the weekend, triggering widespread disruption and blanketing some regions with historically rare sandstorms.

While the unusually strong winds began easing in parts of the south on Sunday, they were expected to continue wreaking havoc across the north, according to the National Meteorological Center.

Northern regions were engulfed by sandstorms, heavy snow and downpours. On Friday, winds measuring between 17.2 and 20.7 meters per second raged across 10 northern regions, including the Xinjiang Uygur, Inner Mongolia and Ningxia Hui autonomous regions, as well as Shaanxi and Shanxi provinces.

Some areas experienced gusts between 37 and 41.4 m/s, according to the national observatory.

The powerful winds triggered alerts for five types of meteorological disasters: gales, snowstorms, sandstorms, torrential rain and severe convective weather, which refers to sudden and destructive conditions such as thunderstorms, hail, strong winds and localized heavy rain.

On Saturday, winds continued to batter the north, toppling trees, ripping off roofs, damaging windows and disrupting air travel. The winds also began sweeping into some southern regions.

Meteorological monitoring over the 24-hour period beginning at 3 pm Friday showed that 493 national observation stations recorded historically high wind speeds for April. Hebei province alone accounted for 95 of those stations, with 61 more in neighboring Henan province.

Tianjin's Jizhou district reported winds between 41.5 and 46.1 m/s — surpassing its previous record set in 1951. In Beijing, winds reached up to 45.8 m/s on Saturday, uprooting more than 800 trees and damaging at least 30 cars by mid-afternoon.

In Henan and Shanxi provinces, winds were strong enough to tear off roofs and shatter floor-to-ceiling windows in some buildings.

As of noon on Saturday, more than 3,200 domestic flights had been canceled, the highest daily total so far this year, according to aviation data provider Vari-Flight.

The winds pushed rapidly southward on Saturday, bringing gusts between 24.5 and 28.4 m/s to Hubei and Zhejiang provinces, as well as Shanghai. Meanwhile, sand and dust storms swept across the provinces of Yunnan and Guizhou and the Guangxi Zhuang autonomous region, sending PM10 particle levels to dangerously high levels.

Xin Xin, a senior analyst at Weather China, said the extreme winds were the result of a clash between strong cold air and warm, humid airflow, combined with a high-altitude cold high pressure system.

"During winter and spring, such a collision can quickly trigger a counterclockwise rotation, giving rise to a temperate cyclone," Xin said. "It's like a spinning weather gyroscope. When reinforced by other atmospheric conditions, it spins faster, as if repeatedly struck by an invisible whip."

Xin added that such systems can rapidly intensify in a short time, creating gale-force winds comparable in strength to a typhoon.

The National Meteorological Center said the winds would begin to subside in the south starting on Sunday. But many areas in the north — including Inner Mongolia, Hebei and Beijing — are expected to remain under the influence of winds up to 30.5 m/s.

At 6 am on Sunday, the national observatory issued an orange alert for strong winds across wide swaths of northern China, effective through 8 am on Tuesday.