NOWSHERA, Pakistan -- "Allah was angry with us when the rain came."



Sumaira Bibi unhesitatingly leans on theology to explain what happened here on the night of July 29, when her world was drowned.



Her husband was out of town for work. The 37-year-old mother was left with her five children and sister-in-law to settle in for the night. Then the incessant rain began to swamp this city in northwestern Pakistan, about 50 miles from the Afghan border. It didn't take long for the water spilling over the doorways to send her family on a desperate bid for survival.



"After six hours, we managed to get out with many of our neighbors, wet and scared," said Bibi, who now takes refuge with her husband and children at a camp run by an Islamic charity group. "The rain still did not stop, but we followed the rest of people who had got a boat."



The sounds she remembers most were the anguished cries of frightened children, women screaming for their loved ones, and the unending rain that caused the Kabul River here to sprawl far outside its banks. She and her children made it to higher ground, but not before losing her home and her brother-in-law, who hasn't been seen since.



"The river Kabul was like a demon, swishing with so much water and overflowing the whole of Nowshera. It is something I have never seen in my life," recalled her neighbor Zunaira, 34, who was pushed out of nearby Risalpur village by the floods. "We had to put a hand on our children's eyes, as they were getting more and more scared with each moment."



The cities of Nowshera and neighboring Charsadda, in Pakistan's Khyber Pakhtunkhwa province (formerly Northwest Frontier province), and their suburbs were the first major communities hit by the unprecedented flooding that swamped one-fifth of Pakistan and left about 7 million homeless this summer. Both women saw scores of buildings, men, women and children swept away by the floods. Though the government puts the death toll for the entire province at about 1,500, almost everyone here believes the actual number of dead is far higher.



These communities found themselves at the epicenter of an unusual weather pattern that dumped record rainfall on northwestern Pakistan and sent floodwaters surging from the north to the rest of the nation.



Residents describing the deluge say it began with a constant, pounding rain that started around July 28 and continued for a week. There were brief pauses of stifling heat and humidity, quickly followed by more rain. It went on that way for over a month. The center of Nowshera was flooded in some places up to 10 feet above street level.



Given such accounts, it's easy to see why Zunaira, Bibi and many other Pakistanis attribute their nation's worst-ever natural disaster to God's wrath. The government attributes the disaster to global warming, but there's more to the story. A ClimateWire investigation into the origins of the flood disaster uncovered evidence that points to a calamity caused by man, the cumulative effect of erratic weather forecast by climate change models, massive deforestation, and lax attention to infrastructure maintenance and engineering standards.



The story of the 2010 flooding in Pakistan is a warning to other vulnerable nations that experts believe will bear the brunt of the gradual shifts in climate and weather patterns expected over the coming decades.



But it's also a sign of how much of the developing world is willfully making itself more vulnerable to climate change, even as poor nations ask rich ones to spend hundreds of billions per year on helping them to adapt. If the industrialized world is to blame for pumping heat-trapping gases into the atmosphere, Pakistanis are also at fault for eroding their country's ability to cope with the consequences.

Final cries of the unrecorded dead

Shehryar Shah, station manager at 93.0 Radio Dilber in Charsadda, remembers the thousands of phone calls his team broadcast over the air from July 28 to alert the Pakistan Army as to where people were stranded. His news and talk station was virtually alone in covering the onset of the flooding as national media attention was fixated on a crash that same day of an Airblue passenger plane in the Margalla Hills, just north of Islamabad.



"We broadcasted these rescue cries for three days, and then we moved to the relief phase," he said.



One of his most painful memories involves a caller indicating that there were about 235 people stuck on rooftops in one part of town waiting for help, calling again and again when no one came. "After two or three hours, there was no more contact with them. Their cell phone was off," Shah said, distraught. "But the government is still insisting just 69 dead in Charsadda."



The SOS calls were interrupted occasionally only by the public service announcements Radio Dilber broadcast on behalf of the provincial disaster management authorities, alerting residents to where the river was breaching its banks and how high it had reached. He described rushing floodwaters up to 20 feet deep in some places. The storm grounded army rescue helicopters for at least two days.



"These people never expected such a huge flood in this region," Shah said. The last time his town was hit by such devastation was in 1929, but even then, the extent of flooding was much lighter, nothing like that seen this summer, he insists.



What Shah and the citizens of Nowshera and Charsadda witnessed in those days was a perfect storm event never before seen in Pakistan's history. Government officials say that from July 28 to Aug. 3, parts of Khyber Pakhtunkhwa recorded almost 12 feet of rainfall in one week. The province normally averages slightly above 3 feet for an entire year.



"We say that there is some part of the climate change effect there in this flooding," said Azmat Hayat Khan, a scientist at the Pakistan Meteorological Department (PMD), part of his nation's Ministry of Defense. "This is an historical event."



What is also exceptional about this year's monsoon, Khan and other PMD officials say, is that it was centered so far north, and over one of Pakistan's driest regions.



The northern section of Khyber Pakhtunkhwa usually sees scattered rains during the monsoon season, but never the deluge it had this year. The inundation even spread as far north as Gilgit and Skardu in Pakistani-administered Kashmir, a mountainous region that had never seen the monsoons.



"Never before have the monsoons gone that far north," said Abdul Qadir, an environment and energy expert at the U.N. Development Programme who is now leading flood recovery efforts in Gilgit. "I think this was the first time in recorded history that there was so much rain in the high alpine areas, and that really basically created these flash floods." Flash flooding led to more deaths in the north than anywhere else.

Monsoons shift away from normal watersheds

Pakistan's monsoon rains normally emanate from moisture swept in over India from the Bay of Bengal. In typical years, the rains open up in the east, centered on Punjab province, roughly near the cities of Lahore and Faisalabad. Experts say the rains then migrate northwest, dissipating by the time they reach the capital, Islamabad, and ending in scattered rains before dying out in Afghanistan.



Isolated flooding incidents occur every year, but Punjab is normally capable of absorbing the monsoon rains. The densely populated province is home to four major rivers that eventually drain into the Indus River, the nation's largest. Punjab is also home to an intricate network of irrigation and water management systems designed for crop use, energy production and flood control.



But for the past few decades, PMD officials have noticed that the center of Pakistan's monsoon has been gradually shifting to the northwest, away from the nation's watershed in Punjab. Whereas flat Punjab is home to long, winding river systems capable of absorbing enormous quantities of water, Khyber Pakhtunkhwa and Federally Administered Tribal Areas on the Afghan border generate relatively shorter and narrow rivers cascading from the mountains that cover roughly half the region.



"Over the past 25 to 30 years, there is a latitudinal redistribution," Khan explained. "Previously, in the past, our flooding was in these river systems [in Punjab], but ... the rainfall has shifted. Its main focus has changed from the eastern parts to the western parts."



PMD believes that climate change is to blame for this northwesterly migration of the monsoons.



The same trend occurred again this year, only farther northwest than ever before, to lands with few major rivers to absorb rains but plenty of vertical surface area to collect water and sweep it downstream. From Lahore and Faisalabad in the east, this year the center and start of Pakistan's monsoon season became instead Nowshera and Charsadda.



And like the fabled "perfect storm" of North Atlantic lore, those monsoon rains eventually collided into two other atmospheric anomalies happening at the same time, creating a perfect storm of their own.



As the monsoons were headed for Pakistan's northwest, from July 25 to Aug. 5 a portion of the jet stream was forced farther south than usual for this time of year by a system of blocking air that mysteriously developed over western China. This buckling of the jet stream dragged with it a wave of low pressure from the west, a system PMD calls the "westerly wave."



This westerly wave low-pressure area collects moisture from the Mediterranean Sea and is responsible for the snows that fall in the Karakoram Mountains. But it usually only comes that far south in the winter months -- in the summer, the normal pattern is for the westerly wave to track north of Afghanistan and miss Pakistan completely.



But because of the blockage of the jet stream's normal course, the westerly wave followed its winter trajectory in late July and early August instead, meeting the monsoon system at Khyber Pakhtunkhwa.



"Subtropical highs that normally redistribute heat in this region, they were shifted northward," said PMD scientist Muhammad Hanif, describing the system that developed over western China that disturbed the jet stream. "This type of interaction is not very usual."

A climate change-related mystery

The cause of this blocking system in western China remains a mystery. Pakistan's Ministry of Environment suspects climate change is to blame, through record high surface temperatures on land. PMD is investigating that, but is also investigating the possibility that the La Niña phenomenon in the Pacific Ocean caused the disturbance. But all agree that the excessive amount of moisture pumped into the atmosphere is a result of high water surface temperatures in the Mediterranean and Bay of Bengal.



That added fuel, and the constrained movement of air caused by the jet stream's dip created a column of rain clouds towering 40,000 feet above Khyber Pakhtunkhwa, much higher than normal monsoon storm clouds, which rarely top 10,000 feet in height. There the clouds stayed for a week, dumping up to 12 feet of excess moisture before traveling to the far west of China, inundating communities there and killing some 1,200 people in landslides.



It was a weather event that the residents of Nowshera, most now either living in camps or in the wrecked hulls of what is left of their homes, say they will never forget.



"These terrible memories will go with me to my grave," camp resident Zunaira said.



"When rain came on Thursday night, we all panicked, it was really very scary," recalled Shamsa, a 16-year-old girl put out of her home and into one of tent cities now ringing the town. "I thought we all were going to drown in floodwaters and die that night, and we had to put up staying on the rooftop of a clinic for two days. But Allah sent the Pakistan Army, who came in their rescue boats and rescued us."



And if this "superflood" event struck at the worst possible place, it also struck at the worst possible time.



Record high temperatures in Pakistan's far north were already producing higher amounts of snowmelt and glacial meltwater runoff from the Karakoram Range and into the Indus River System. Thus, the Indus and other rivers were already swollen with water in the north by the time the supercell of rains from east and west merged above them.

Rivers already filled with 'glacial bursts'

"We have been noticing these glacial bursts from the last couple of years," said Hameed Ullah Jan Afridi, Pakistan's minister for environment, in an interview. "This is not the first time, so that was in addition to the floods which happened."



The result for Pakistan's northwest was flash flooding that killed at least 1,500 people, according to government estimates; washed out numerous bridges; and destroyed a section of the fabled Karakoram Highway, cutting off half a million people from the outside world. At least 70 percent of both Nowshera and Charsadda was completely swamped, as nearby rivers and streams proved incapable of handling the water that came crashing down from the highlands.



The south of Pakistan wasn't spared.



Khyber Pakhtunkhwa's perfect storm was followed on its heels by a second wave of weather that dropped heavy monsoon rains over the Punjab watershed from Aug. 2 to 9, Khan said.



These storms were also strong, with Mianwali, a city at the heart of the downpour, recording 20 inches of rainfall in three days. That more normal monsoon pattern arrived just in time to catch the record volumes of rainwater streaming down the Indus river system from the heavily hit northwest.



Massive torrents of water from the Jhelum, Chenab, Ravi and Sutlej rivers fed by these monsoon rains eventually met the Indus at Rajanpur district in southern Punjab. From there, the waters flowed south into Sindh province on their way to the ocean, spilling far beyond the Indus' banks. Floodwaters also spread west into Balochistan, causing devastation there, as well.

A disaster seen from space

This summer's catastrophe was continuously fed by rainstorms that hit the nation sporadically until around mid-September, though Pakistanis say their monsoon season typically concludes at the end of August. At its height, the floodwaters could be seen from space, with the Indus spreading more than 20 miles wide at some parts.



Every province was hit, and all told, 20 million Pakistanis are said to have been affected in some way by the flooding. About 1,800 are thought to have perished, though Pakistani aid workers and victims dispute the relatively low number, nothing that thousands are still probably missing.



The destruction of hundreds of thousands of homes has forced an estimated 8 million to sleep under tents, in makeshift shelters or out in the open. Thousands of acres of cropland has been destroyed just as planting season was to commence, and roughly 10 million head of livestock are believed to have been killed.



Both the United Nations and Pakistani government officials are convinced that climate change was the key contributing factor to the devastation. The cycle of dry spells that Pakistan has suffered for the past few years, terminated by a massive torrent, aligns almost precisely with trends predicted in the assessment reports of the Intergovernmental Panel on Climate Change.



Environment Minister Afridi says his government plans to drive that point home to other nations at climate change talks scheduled for Mexico at the end of this year.



"We are going to Cancun," Afridi said. "We are looking forward to having a forum where we can cry in front of those people and have them know what has happened with us. The world has seen it themselves."



But Afridi also acknowledges that in many ways, Pakistan set itself up for an even bigger disaster than would otherwise have transpired. Ecological degradation that he says costs his nation about $1 billion in lost wealth per day is also partly to blame.



To what extent the 2010 flood disaster was caused by climate change versus other human impacts is a subject of growing debate in Pakistan.



Next: Part two -- how ecological degradation and neglect made the disaster far worse.



Saadia Haq contributed to this report.



Reprinted from Climatewire with permission from Environment & Energy Publishing, LLC. www.eenews.net, 202-628-6500