The worst typhoon in a decade batters Taiwan and China. The most severe drought in memory shrivels up North Korea. In Hong Kong, the rainfall for June and July breaks all records. Beijing bakes in a heat wave. In the Philippines, Manila is washed out, for the second time this year. Northern Australia and Indonesia experience semi-drought conditions.

Something distinctly odd is happening to the Pacific climate pattern. Asian meteorologists examining the weather phenomena have arrived at the inevitable conclusion: El Nino is back.

What's worrying the weather forecasters is that this El Nino, which disrupts seasonal atmospheric circulation on a global scale, is bigger and badder than usual. According to meteorological data gathered all across the region, it is shaping up to exceed the strongest episode in the last half century - the 1982-'83 El Nino which was marked by unusual storms and downpours, bringing death and destruction in their wake.

El Nino is the name given to the periodic increase in sea-water temperatures from the coast of Peru to the equatorial central and eastern Pacific. It occurs on average once every four years, though sometimes the interval can be three or five years, and it can last 18 months. There have been 11 El Ninos in the last 46 years. The last one was in 1994.

At present, sea-surface temperatures over the equatorial central and eastern Pacific are much warmer than normal, and higher than the record 1982-'83 period. "Indications are that these warm conditions will persist for the rest of the year and if so, 1997 will be an El Nino year," said a senior scientific officer at the Hong Kong Observatory.

Another phenomenon closely related to El Nino is the Southern Oscillation. This is the phenomenon whereby whenever pressure is high over the equatorial Pacific it will be low over the Indian Ocean, and vice versa. It is measured by subtracting the pressure at Darwin, Australia, from that at Tahiti, halfway across the South Pacific Ocean. El Ninos have always produced a minus figure. That is happening now.

When El Nino occurs, convective activity over the western Pacific and the South China Sea is reduced and tropical cyclones and typhoons (or hurricanes), tend to shift to the central Pacific where the warm water has gathered. This may explain why Hong Kong was let off the hook when the big violent storms started coming in.

"Coincidentally, up to the end of July this year only one tropical cyclone, Victor, occurred over the northern part of the South China Sea," said the Hong Kong Observatory. "In Hong Kong, no tropical cyclone warnings were hoisted until July 31st, when this was necessitated by the approach of Victor. This is the first time since 1946 that tropical cyclones did not affect Hong Kong until so late in the season."

But of the 10 wettest winters in the territory in the last half-century, seven coincided with El Nino, and this year the downpours have been non-stop. Hong Kong soaked up as much rain up to the end of July as it does in an average year. No one who was in Hong Kong on the night of June 30th-July 1st, when the territory reverted to China - not least the People's Liberation Army soldiers entering the territory on open lorries - will forget the intensity of the precipitation just before dawn, when Hong Kong had a rare "black rain", i.e. 100 millimetres in two hours.

The warmer water in the central Pacific most likely decided the intensity and the northerly path of Typhoon Winnie, which tore into Taiwan on Sunday and Monday, killing at least 37 people. Bodies were still being dug yesterday from collapsed buildings where 16 people were crushed or drowned in Hsichih, Taipei, after a hillside apartment complex was shifted like a deck of cards by mud slides. Twelve people are still missing.

The hurricane then howled across the Taiwan Strait into eastern China on Tuesday, killing over 150 people. It could have been worse but for the quick action of Zhejiang Province officials, who moved a million people inland. Luck played a part too. The hurricane veered south at the last moment and spared the densely-populated metropolis of Shanghai. Chinese television showed pictures of extraordinary devastation in nearby regions, with debris-filled streets and broken sea dykes. In Taizhou city, at least 50 people are dead or missing. Winnie then moved north through Jiangsu to Anhui province, where it dumped torrential rain before dissipating, flooding tens of thousands of homes.

China is so big there are always floods and droughts somewhere. This time last year five million soldiers and peasants were battling the rising waters of the Yangtse River, which flows into Shanghai; the floods eventually claimed thousands of lives in Wuhan province. El Nino is most likely responsible for the people on the Yangtse flood basin getting a break this year.

Every cloud has a silver lining. The weakened storm headed north up the Yellow Sea as a tropical depression, past the estuary of the Yellow River (whose regular floods used to be called China's Sorrow), which this year has dried up because of the drought in central and north-eastern China. It arrived yesterday in North Korea, bringing welcome rain to regions which had not seen a drop for 80 days.

The drought in North Korea has been a calamity. About 70 per cent of the maize crop in the ill-fated communist country has already been lost, adding to the misery of a people who in the last two years had to endure floods which wiped out the grain crops. At least now the rice crop might be saved, bringing some respite to a hungry people.

But for many months to come, the peoples of the Pacific rim can only wonder what more surprises El Nino has in store, and meteorologists try to calculate whether its abnormal strength is cyclical or further evidence of global warming.