Shanghai, China ? With Typhoon Kaemi roaring toward China’s crowded southeast, Dr. Yang was sealing his apartment windows against the pounding rain when his cell phone buzzed to life.

“Typhoon forecast to make land this evening,” said the message sent to millions of mobile phones in the coastal city of Jinjiang and surrounding Fujian province. “Please attend to preparations.”

Once the domain of gossipy teenagers, text messages have become a key tool for Chinese authorities during this year’s unusually powerful typhoon season.

Nearly one-third of China’s 1.3 billion people has a cell phone, creating a rival to television and radio as a way to reach the public.

Authorities in Fujian have sent 18 million messages – known as SMS, for short message service – with storm information during five typhoons this year, according to the provincial government.

Although residents complained of poor execution, many praised the idea of using text messages to send storm warnings.

“Technology is improving, and I think the government sending messages to warn of natural disasters is pretty smart,” said Dr. Yang, who works at Jinjiang’s Chinese medicine hospital and would give only his surname.

Chinese residents salvage what's left of their belongings after a flash flood when Kaemi weakened into a tropical depression and made landfall Wednesday in southern China's Jiangxi province. As Typhoon Kaemi roared toward China's southeast, many residents received a text message from the government warning them of the storm.

China’s population of cell phone users – the world’s biggest – long ago surpassed the country’s 365 million fixed-line phones, and is growing rapidly.

It isn’t unusual to find villages with no fixed lines but dozens of cell phone customers.

The government has encouraged the spread of mobile phones because their infrastructure is cheaper than fixed-line phones, which require expensive networks of wires to link homes and businesses.

The government also has used text messages to reassure the public about bird flu outbreaks and to warn against supporting the banned Falun Gong spiritual movement and taking part in unauthorized protests.

“Obey the law. Maintain order,” said a message sent to millions of phones in Shanghai and Beijing last year in an effort to rein in violent anti-Japanese protests.

In part, the government was playing catch-up to political activists.

Although text messaging is exploding, with 25 billion messages sent each month, the storm warning system is still in its infancy.

Some Jinjiang residents said they knew Kaemi was coming before getting the messages and didn’t do anything differently because of them.