Story highlights Haikui's winds are at "severe typhoon" strength as it hits eastern China

More than 600,000 people have been evacuated from affected areas

Haikui is the third tropical cyclone to hit China's east coast in less than a week

Typhoon Haikui slammed into the east coast of China on Wednesday morning, pummeling the area around the business metropolis of Shanghai with heavy wind and rain.

The storm's winds were at "severe typhoon" strength when it made landfall in the province of Zhejiang, about 225 kilometers (140 miles) south of Shanghai, the China Meteorological Administration said. The winds diminished to typhoon strength as Haikui moved inland.

A severe typhoon is considered to have maximum sustained wind speed of between 150 and 184 kilometers per hour (93 and 114 mph). A typhoon has maximum sustained winds of between 118 and 149 kilometers per hour (73 and 93 mph).

Hundreds of thousands of people had been evacuated from Haikui's path as it approached, the third tropical cyclone to hit China's east coast in less than a week.

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Chinese officials had relocated 374,000 people from Shanghai and 250,000 from Zhejiang, according to the state-run newspaper China Daily.

Although the storm's winds are expected to weaken as it moves overland, it will continue to dump large amounts of rain on the surrounding area, raising the risk of landslides and flooding.

"The rain is the bigger impact going forward," said CNNI Meteorologist Taylor Ward. "We have already had up to 8 inches in some locations."

Ward said another 6 to 10 inches of rain were expected to fall, with "maybe isolated amounts greater."

Haikui was moving northwest at 20 kph (12 mph) but was expected to slow over the coming two days, he said.