Earlier versions of this story misstated the names of an organization and a journal. The organization is the World Meterological Organization, not the World Meterological Association, and the journal is Geophysical Research Letters, not Geophysical Review Letters. This version has been corrected.
Devastating 2010 Pakistan floods highlight difficulties in sounding alarm
Monday, February 14, 2011
Last July, a set of troubling numbers appeared in a computer at a key weather-forecasting center west of London.
Expect massive, unprecedented rainfall in northwest Pakistan, the numbers said.
But nobody at the center noticed, and officials in Pakistan failed to interpret the signal as a warning.
So the data went unheeded, exposing deadly gaps in the world's loose network of weather prediction systems.
On the day of the heaviest downpour in northern Pakistan, July 29, ten inches of monsoon rain pounded the largest city in the area, Peshawar. The subsequent floods overwhelmed the country, inundating an area about the size of Italy. Two thousand people drowned, and 20 million more - 12 percent of Pakistan's population - were displaced. The disaster also destroyed billions of dollars' worth of infrastructure, crops and livestock.
If data from the European weather center had been properly analyzed, Pakistan could have been warned more than a week ahead of the calamity, an independent flood-prediction expert is now saying. There was "80 percent probability [of severe rain] eight to nine days out," said Peter Webster of the Georgia Institute of Technology, who examined the European center's data. Webster will publish his analysis, which he performed months after the floods, in an upcoming issue of Geophysical Research Letters.
The incident highlights both the growing sophistication of computer programs to predict extreme weather and the difficulties in communicating that information to an anxious public.
The multinational center whose computers foresaw the extreme rain - the European Center for Medium-Range Weather Forecasting - simply does not have the resources to provide specific weather forecasts to individual nations, said Manfred Kloeppel, scientific and technical assistant to the center's director. No one at the center saw the danger signal in advance, Kloeppel said, but "even if someone had noticed this, it is simply not our role to take the phone and call someone."
Instead, the center runs continuous global weather simulations on its computers. Daily summaries are posted online for members of the World Meteorological Organization, which includes Pakistan, to use as they see fit.
The head of Pakistan's weather service said that his agency did forecast heavy rains four day ahead of the deluge, in part by using the European data. But the agency "missed" on predicting that the rain would be so extreme, said Arif Mahmood, director general of the Pakistan Meteorological Department, in an interview from Islamabad. Never in memory had the summer monsoons that soak much of South Asia veered so far west.
Mahmood lamented the information gap that left potentially lifesaving data sitting unnoticed on computers in England.
"Nobody informed us," he said. "If there is the capacity to predict this, they must inform the World Meteorological Organization or the government of Pakistan that this type of emergency is coming."