Sandstorms, which normally attack Beijing in spring, hit the capital city Monday afternoon on an early summer day.

This was rare in history, said Zhang Mingying, a senior engineer of the Beijing Municipal Meteorological Observatory.

At about 6:00 p.m. on Monday, a gust of wind swept Beijing suddenly swirling with sand and earth. The wind speed rose sharply to seven meters per second and the sky turned dark yellow within one to two minutes. This lasted for 20 minutes.

Zhang confirmed the sandstorm and said the sand was mainly from local places of Beijing, instead of other regions.

Since early June, the temperature in Beijing has kept very high, even up to 38.9 degrees C. for some time. Continuous hot and dry weather has increased the amount of floating earth in the city, said Zhang.

"The heat also made the atmosphere unstable and caused the strong gust," said the expert.

Records show sandstorms mainly happened in March and April in Beijing and were rare in May and June, though the city had once been reported to suffer sandstorm in July.

Sandstorms have posed a grave environmental scourge of northeast Asia. Almost every year from March to May since the late 1990s, strong cold winds from Siberia blow up a huge volume of yellow dust to Beijing from the vast Gobi desert in Kazakhstan, Mongolia and northwest China.

(Xinhua News Agency June 16, 2004)