Get ready for nasty wet winter – again – weather experts say.
“La Niña conditions have returned and are expected to gradually strengthen and continue into the Northern Hemisphere winter 2011-12,” says a warning issued on Sept. 8 by the U.S. National Weather Service of the National Oceanic and Atmospheric Administration.
That means, like last winter’s La Niña, there’s another strong chance of above-average precipitation across the Pacific Northwest, says the alert. A second La Niña this soon is unusual, according to the U.S. agency.
It and its warm and dry opposite, El Niño, occur on average every three to five years with La Niñas usually half as frequent.
“While it is not yet clear what the ultimate strength of this La Niña will be,” the warning says.
The last La Niña developed in mid-2010 and lasted until this spring. The impressively strong La Niña in 2010-11 was partly responsible for the record U.S. winter snowfall. That in turn led to spring flooding, extreme drought conditions across the United States, as well as extreme weather events around the world.
That year saw heavy rains and monsoons in Asia, the devastating and fatal cyclones in the north east of Australia, and an extremely dry period in equatorial eastern Africa.