If I'd been told two weeks ago that the annual monsoon rains in Pakistan would devastate so much of the country, affecting so many, I would have raised an eyebrow at the remark.

But watching the story unfold from Doha's presenter desk last Thursday, the pictures of devastating flooding in Pakistan confirmed that these were not just your regular rains this was much bigger.

Our teams had been mobilised on Wednesday and by the time the water hit Islamabad it was clear that this was a more serious situation than any of us imagined.

I was deployed to Islamabad with a view to moving to the Swat Valley as the crisis unfolded, while my colleague Kamal Hyder was to follow the flow of the floodwaters to the Punjab.

We are talking about an area the size of the UAE, Wales or the American states of Vermont, Maine and New York combined. It's huge and every square kilometer has been affected.

Scale of diaster

The pictures on Al Jazeera give a sense of the scale of the disaster. This event may not have killed as many people as the 2005 earthquake, which left up to 85,000 dead, but it's affected many time that.

A week after the flooding began, the UN estimates 12 million people have been displaced and the death toll is expected to rise as the torrent of floodwater follows the rivers south.

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In its wake, it is leaving scenes of destruction, with entire villages swept away and fertile agricultural land covered in a thick layer of mud.

The roads leading out of Mingora, where we’re based in the Swat Valley, are bad at the best of times. Now, if they exist at all, they are almost impassable.

The only way to get to some of the most isolated places in the valley is by four-wheel drive truck – a trip we took this week.

En route, the land has been carved away from the sides of hills like slices of cake by the swollen River Swat. Bridges - over 65 across this region alone - have been washed to one side, breaking the only link between communities stranded by the rains and those trying to reach them.

Our journey north came to an abrupt end at Fathipur, where the narrow road that until last week ran along the edge of the river has been washed away. On the other side of the gap, we can see the town of Madian, whose 200,000 inhabitants have been cut off from the outside world for over seven days.

Rescuers were making their way over hills to get to them, embarking on an arduous journey that could take up to 10 hours, if they can find a route over mountainous terrain at all.

Bridges lost

Surveying the scene from the air, the scale of the disaster on the ground becomes clear. Flying over the river, it is clear that bridge after bridge is gone, each one another community's link to the outside world.

So how did this happen?  Local officials say that the volume of monsoon rain was simply never forecast. When it fell, witnesses say that the unprecedented downpour caused 20-foot waves as the water coursed through narrow gorges.

Given the ferocity of the rains, it is no surprise that everything on the river-bank was either swept away or submerged.

On Thursday, exactly a week and a day after the rains began to fall, the Pakistani military took us to Kalam, 150 km north of Mingora. Thousands of tourists had been stuck here for days, with no food, water or sign of rescue until the helicopter arrived.

Further up the valley, hundreds of thousands of people are still waiting for assistance.

Growing anger

It may be slow in coming, but help is on the way. The international community is flying in food aid and American helicopters are boosting the rescue efforts so urgently needed in the north.

But the crisis is not over. Rains are continuing to fall in the north of the country and the floodwaters are still running south. The states of Punjab and Baluchistan have already been hit, and there are growing concerns over what will happen in Sindh.

By Friday, Al Jazeera had confirmed that up to 40,000 people had been evacuated from vulnerable areas in Sindh ahead of the anticipated floods. It is not clear how much longer Pakistan will have to endure this crisis, but with no shelter, these people are adjusting to a new home a field under open skies.

Anger at the Pakistani government is growing. Many of the displaced people have told Al Jazeera that they feel they let down by the government's response, and as the country braces for further crisis, they say that the officials elected to protect and serve the people of Pakistan have failed them in their hour of greatest need.