La Nina is back
The ocean-atmosphere phenomenon promises to disrupt the weather across the globe once more.
Last Modified: 09 Sep 2011 14:19
La Nina triggered the flooding in Australia which was the worst in decades [Al Jazeera]

La Nina is the name given to the slight cooling of the surface waters of the Pacific Ocean, and it is known to disrupt the weather around the world.

The previous La Nina only faded away three months ago. It was June when the waters of the Pacific were observed to have returned to normal, and slowly the effects on the atmosphere were easing as well.

This last La Nina was one of the most intense on record. It stayed in place for about 15 months, and caused havoc around the world.

Some parts of the globe, including Southeast Asia and Australia, expect flooding during a La Nina year, but even here, the sheer scale of the flooding caught people by surprise.

Torrential rains triggered mudslides in the Philippines and Indonesia, and the worst flooding for decades swamped Australia.

Colombia was also badly hit. The flooding here was described by the country’s president, Juan Manuel Santos, as the “worst natural disaster”.

Even Sri Lanka, which is normally unaffected by La Nina, was inundated.

In the Pacific, the La Nina conditions extended further west than usual, which in turn pushed the rains across the Indian Ocean further west as well.

This ensured that the storms which would normally stay over the sea, actually hit Sri Lanka instead, leading to the evacuation of hundreds of thousands of people.

La Nina does not only bring flooding, but can affect other aspects of the weather as well.

In northern Asia, La Nina would often bring a severe winter, and this was no exception. In February, one storm alone dumped 80cm of snow on South Korea, and temperatures in the region stayed below average for days on end.

La Nina also increases the number of hurricanes seen during the Atlantic hurricane season.

More active than usual

The previous La Nina has only just eased, so its impact is still being felt. This is why the current Atlantic hurricane season is more active than usual.

And La Nina can also cause a reduction in the amount of rain. For the southern states of the US, this deficit of rain has led to a severe drought. This in turn, triggered wildfires, which swept across the region, destroying thousands of homes.

The lack of rain was also seen across the Horn of Africa. Currently 12 million people are in danger of starvation across the region. The next rains were expected in November.

The La Nina conditions have returned, and now are expected to strengthen over the next few months. The effects of this will again be seen around the globe.

Australia, Indonesia and the Philippines can expect to see flooding once more, and the residents of northern Asia should brace themselves for another severe winter.

The end of the Atlantic hurricane season is likely to become even more active, and Texas is likely to remain in a drought.

However, perhaps most devastating are the consequences for eastern Africa. With La Nina steadily strengthening, the November rains are likely to fail once more.

This would have dire consequences for the millions of people who live in the region, many of whom are already struggling to survive.

Al Jazeera
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