Her name may be Spanish for "little girl," but La Nina - a weather pattern related to better-known bigger brother El Nino - can hold her own.

She is capable of causing extreme weather around the world, as Atlantic Canada discovered this weekend at the hands of Noel, a storm that packed winds of 135 kilometres an hour and waves as high as 15 metres.

And there's more to come. The United Nations weather agency warns that this little girl is going to be with us for the next five months, and that could mean a bigger finish for the last month of Atlantic hurricane season, as well as heavy rain, a colder winter and more snowfall.

"These conditions can cause unusual and sometimes severe weather events ... in the immediate area of the Pacific basin but also around the world," Leslie Malone, a scientist with the World Meteorological Organization, said last week.

Generally, scientists say, La Nina is not as damaging as El Nino, the better-known weather pattern that came to the world's attention in 1997-1998 when it wreaked havoc with storms around the Pacific Rim.

"La Nina is the evil twin sister of El Nino, so it's good or bad depending on where you live," University of Victoria meteorology professor Andrew Weaver told the Associated Press earlier this year.

La Nina, sometimes called El Viejo, or a "cold event," is the opposite of El Nino, when waters in the central and eastern Pacific are unusually warm. With La Nina, the Pacific waters off the coast of South America and beyond are unusually cool, thanks to stronger trade-wind circulation, which takes warmer surface water off toward Asia and leaves the cold stuff behind.

According to the World Meteorological Organization, surface temperatures in this part of the Pacific are up to 1.5 C cooler than normal at the moment, which it says is in the mid-range of La Nina events on record.

This change is supposed to cause more cloud cover, and much more rain, in places like Australia and Indonesia, during our winter. But this time, ocean temperatures in Asia remain unusually cool, too, and so may not produce the expected La Nina results in that region, the WMO says. In Australia, where a lengthy drought is punishing farmers, they could use the rain.

La Nina's atmospheric mischief also changes the nature of the jet-stream air current that flows across North America from west to east, altering its normal path. The results on this continent can mean a mixed bag of sometimes wacky weather: On the West Coast, it could mean even more precipitation - southern B.C. is currently soggy with rain - as well as a longer and colder winter, a combination that already has ski resort operators feeling hopeful.

In other parts of Canada, including the Prairies, Ontario, Quebec and Atlantic Canada, La Nina has in the past brought colder winters and massive dumps of snow.

In the Southern United States, it means drier and warmer weather - bad news for Texans, already enduring a drought, and for Southern California, where wildfires remain a concern. In Africa, disastrous floods have killed 200 people and left hundreds of thousands displaced in 17 countries, including Kenya and Sudan.

But La Nina's most threatening power may be its effect on hurricane season in the Atlantic basin, where scientists say it reduces the "vertical wind shear" that often weakens large powerful storms as they develop.

Hurricane predictors, including Colorado State University's William Gray - regarded as one of the world's foremost hurricane experts - had predicted above-average Atlantic hurricane activity as La Nina emerged. So far, there have been 14 named storms, slightly more than the typical 9 to 12, and the season ends at the end of the month. It was unclear whether more hurricanes or their remnants could be expected to churn up the East Coast as a result of the current La Nina.

According to Environment Canada, a "moderate La Nina" was in effect in 1954, the year Hurricane Hazel slammed into Toronto, washing entire houses into the lake, leaving thousands homeless and killing 81 people, including 30 on one street alone.

RECENT MAJOR LA NINA YEARS INCLUDE:

1995-1996, which Environment Canada says resulted in a long, cold winter with temperatures averaging as much as 2 degrees below normal in most of the country, and more than normal snowfall in the southern Prairies, Southern B.C., Atlantic Canada and the Arctic.

1988-1989, when the country enjoyed a mild winter until bitter cold set in at the end of January, 1989, Environment Canada says, plunging temperatures on the Prairies into record-breaking -30 and -40 C range. Vancouver was unseasonably cold, and it even snowed in Southern California.

AROUND THE WORLD WITH LA NINA

The weather paths caused by the phenomenon know as La Nina - the opposite of El Nino - straddle the globe.

Africa: At least 200 people are dead and hundreds of thousands homeless after floods in recent months in central and eastern Africa.

Asia and Australia: The Indian subcontinent and Indonesia, as well as Australia, would usually expect torrential rains from La Nina. But this year, sea temperatures north of Australia up to the Indian Ocean are also cooler than expected, and for the most part dry conditions continue to dominate.

Jet stream: La Nina shifts the point at which the jet stream normally hits North America, changing the path of storms.

Western Canada: La Nina should mean colder temperatures and may be to blame for the heavy rains soaking southern British Columbia.

Central Canada: While the last major La Nina, in 1995-1996, did bring a strange warm spell in January in Ontario and Quebec, her real gifts were unusual cold and extreme amounts of snow.

Southern U.S.: The South, including the southwest, is expected to be drier and warmer than usual, bad news in the wake of California's forest fires.

Atlantic basin: Experts warn that La Nina tends to worsen Atlantic hurricane season, since it reduces "vertical wind shear" that usually weakens growing storms in the tropical North Atlantic and the Caribbean Sea.

La Nina: The phenomenon starts when stronger trade winds produce cooler than average waters in the eastern and central Pacific Ocean, near the coast of South America -- the opposite of El Nino. Right now, they are up to 1.5 C colder than normal.

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www.standeyo.com/NEWS/07_Earth_Changes/071106.La.Nina.fueled.Noel.html