To All: Everything You Ever Wanted To Know About El Nino...And More!!
The Canadian
El Ni¤o Bulletin
Environment Canada's
www.weatheroffice.com
Environment Canada scientists are tracking the strongest El Ni¤o in a century and a half -
and the news is good for most Canadians looking for respite from winter cold and a reduction
in home heating costs.
El Ni¤o is disrupting weather patterns in many regions of the world and has already been
blamed for droughts, torrential rains, sweltering heat and severe crop failures. Scientists are
calling it "the climate event of the century."
In Canada, the southern regions can look forward to a warmer winter with less rain and snow
than usual, while northern regions and the Atlantic provinces can expect normal winter
weather.
El Ni¤o is a warming of waters in the eastern Pacific Ocean near the equator thought to be
caused by changes in the normal patterns of trade wind circulation.
Normally, these winds move westward, carrying warm surface water to Indonesia and
Australia and allowing cooler water to upwell along the South American coast. For reasons
not yet fully understood, these trade winds can sometimes be reduced, or even reversed. This
moves warmer waters toward the coast of South America and raises water temperatures.
Warmer water causes heat and moisture to rise from the ocean off Ecuador and Peru. The
result is more frequent storms and torrential rainfall over these normally arid countries. The
added heat also strengthens and alters the path of the jet stream affecting weather patterns
worldwide. In North America, this typically means the jet stream splits in the North Pacific,
diverting storms toward the Yukon and Northwest Territories, while leaving most of southern
Canada with a milder and drier-than-normal winter.
How does this year's El Ni¤o compare with other El Ni¤os?
This year's El Ni¤o shows signs of being the strongest since extensive sea surface
temperature observations began in the earlier half of this century. Its strength may surpass
even the 1982-83 event, which at the time was dubbed "the El Ni¤o of the century."
Surface temperatures of the Pacific Ocean off the coasts of Ecuador and Peru are
currently about 5øC above normal, the highest observed in the last 50 years. These warm
waters occupy an area of about 14 million square km - about 1 « times the size of
Canada. Sea surface temperatures off Canada's Pacific Coast, meanwhile, are averaging
about 2 to 3øC above normal. Such strong El Ni¤o conditions present climatologists with
the best opportunity ever to produce reliable seasonal predictions.
What is this year's El Ni¤o expected to bring for Canada?
El Ni¤o does not mean that the winter of 1997-98 will be without cold, storms and
blizzards. However, Environment Canada experts foresee the likelihood of a
warmer-than-usual winter - at least from British Columbia through Ontario and southern
and central Qu‚bec. Drier-than-normal conditions are expected from the B.C. interior
through the Prairies and into the Great Lakes basin. This could mean reduced amounts of
rain and snowfall, together with higher temperatures and lower home heating bills. The
North West Territories - including the Arctic islands -- and the Maritime provinces do not
normally experience the effects of El Ni¤o.
The map shows typical winter temperature responses to El Ni¤o. The numbers
indicate degrees Celsius by which the temperature departs from normal. The line
across Northern Canada delineates areas of above and below normal temperatures.
What are El Ni¤o's global impacts?
As always, the effects of El Ni¤o are more direct and dramatic in the tropics. Some
impacts of this year's El Ni¤o in these areas include:
Severe drought in some areas of Indonesia due to the early arrival of the dry
summer season. This has contributed to the extreme forest fires that
blanketed South East Asia in smoke and haze.
Severe storms in central Chile in June, July and August, with rainfall totaling
10 times the normal amount for an entire year. Santiago, the capital,
received more than a year's worth of rain (300 mm) in June.
The worst drought in 50 years for Papua New Guinea.
Crop and livestock losses from dry weather already exceeding $130 million
in New Zealand.
Sweltering summer heat in areas of Asia from the Indian subcontinent to
China, including the most severe heat wave this century.
Unpredictable monsoons in Pakistan and northwestern India, with spotty rain
in some areas and torrential rain in others.
El Ni¤o is expected to cause much higher than normal winter rainfall for the
southern United States, possibly producing severe flooding in California and
Texas while bringing cooler and wetter weather to Florida.
What has been the impact of previous El Ni¤os?
El Ni¤os alter weather patterns around the world, causing abnormally high
rainfall in areas that normally do not see much rain, and drought in areas
that are accustomed to more precipitation. The 1982-83 El Ni¤o was the
most disruptive recorded to date. It had dramatic effects around the world,
including Australia's worst drought in 200 years. Overall, it was responsible
for more than $18 billion in economic damages and 2,000 deaths.
Each El Ni¤o brings with it its own characteristics. The current El Ni¤o is
already as strong as the 1982-83 event, which had significant impacts on
Canada, including:
A mild winter in most of southern Canada saw one-half the normal snowfall
from British Columbia to southern Quebec and temperatures anywhere from
3 to 6øC above normal in these regions. Vancouver snowfall was only 4 cm,
compared to an average of 50 cm, while Ontario had its mildest winter in 30
years and Toronto had its third mildest winter since 1840.
Among the positive results of this mild weather were reduced snow clearing
budgets for municipalities, heating costs 5 to 15 per cent below normal for
homeowners and businesses - an average savings of $200 per household -
and a reduced risk of serious spring flooding because of the lack of snow
and ice congestion in rivers. As well, sockeye salmon deserted U.S. waters
and headed for the cooler Canadian waters.
On the other hand, British Columbia experienced flooding and landslides
resulting from strong winds, mild temperatures and wet snow. Avalanches
were common in the southern B. C. interior.
There were severe economic impacts when inadequate snow cover and mild
weather virtually eliminated skiing in southern Quebec and southern Ontario
during the usually busy Christmas and New Year holiday period. Several
people drowned when they ventured onto thinner-than-usual Great Lakes ice,
while heavy coastal ice and numerous ice bergs impeded navigation on the
Eastern Seaboard.
The northeastern Arctic did not benefit from El Ni¤o and, in fact, experienced
bitterly cold weather, with temperatures plummeting to -40øC for prolonged
periods.
Is there a link between climate change and El Ni¤o?
Scientists are questioning whether climate change may be affecting the
observed increase in strength and frequency of El Ni¤o events in recent
decades, or whether the El Ni¤os themselves are contributing to global
warming. There is no consensus yet on any direct link. Further research is
needed before scientists can provide confident answers to these questions.
.
The phrase "El Ni¤o" refers to the Christ Child and was coined by fishermen
along the coasts of Ecuador and Peru to describe the warm ocean current that
typically appeared around Christmas time and lasted for several months.
El Ni¤o is the second largest driver of the world's weather, second only to
normal seasonal warming and cooling, which also brings changes in
precipitation patterns.
El Ni¤os appear approximately every two to seven years. They typically last 12
to 18 months. In the early 1990s a protracted El Ni¤o persisted for four years.
El Ni¤os have been documented since the early 1700s. More detailed
observations from ships led to instrumental record keeping in the earlier half of
this century. It is only since the 1970s, however, that scientists began linking
El Ni¤o to massive flooding and severe droughts around the world.
About every four to five years, a pool of cooler-than-normal water develops off
South America. The effects of this cooler water are called La Ni¤a. This usually
brings colder winters to the Canadian west and Alaska and drier, warmer
weather to the American southeast.
Click here for a detailed look at the potential impacts of El Nino on
British Columbia |
