Channel 4 News Alex Thomson reports from Kamaishi where blizzards and ice now blanket a village whose massive tsunami protection walls failed to save its people last Friday.

Kamaishi - snow covers the many dead (reuters)

Roads, bridges and the huge concrete anti-tsunami walls in the northern town of Kamaishi have been destroyed.

Now severe winter conditions are preventing search and rescue teams from reaching the area. More snow is forecast across the Sendai region in Japan overnight and into Thursday with temperatures hitting a daily low of minus four, and expected to stay the same into the weekend.

Chief Correspondent Alex Thomson says Kamaishi residents are asking:"What have we done to deserve a historically powerful earthquake, the vast tsunami damage, and now a blizzard?"

So far, more than 4,000 people have been confirmed dead. But the death toll is set to climb further as teams reach the hardest-hit areas.

"It's so cold here. We need kerosene and petrol," says a local man as he waits for any assistance to arrive.

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With thousands still missing and hundreds of thousands of people having lost their home, the weather could be yet another silent killer to heap more heartbreak across north eastern Japan.

As Jon Snow reported on Tuesday night, in the inland towns now being used by coastal refugees, concerns over nuclear fallout are being pushed into the background as people deal with dwindling food and medical supplies and now the crippling icy temperatures.

Destruction

Alex Thomson's visit to Kamaishi underlines the enormity of the destruction visited on northern Japan last Friday.

He writes: "We have seen destroyed factories, indeed whole towns, but we have never seen anything like the ruins of Kamaishi today. It's not just that the town has been largely destroyed - sad to say, that is a commonplace in the tsunami zone. It's that so much had been done to protect this area from major tsunamis.

"What I mean is this: the huge concrete sea walls built around the bay here. You walk along them and they must be at least 25 feet high. At the top, you are walking along something perhaps eight or ten feet wide. And the walls fan out from your feet down to the water level 30 feet below, and at that point they must be at least 30 feet wide.

"So you are talking vast amounts of concrete used here, because only this much concrete will protect the bay.

"Well, that was the plan.

"In fact, today, in the ceaseless, driving snow, you can see that the walls had been not just breached but ripped apart by the extraordinary violence of the tsunami. That meant that the areas behind took the full force, which they never expected to take.

"They thought they were safe. After all, that is why they built the walls in the first place, wasn't it?"

Meanwhile in Tokyo, Jon Snow is witnessing how the elements, for now, are actually keeping people to the south safe: "For the moment the population is being saved by the wind. I glimpsed the wind sock as I landed at the airport close to town here, it was billowing directly out to sea but if that changes the threat level changes with it."