Soma, Japan ? The second hydrogen explosion in three days rocked Japan’s stricken Fukushima Dai-ichi nuclear plant today, sending a massive column of smoke into the air and wounding 6 workers. The plant’s operator said radiation levels at the reactor were still within legal limits.

The explosion at the plant’s Unit 3, which authorities have been frantically trying to cool following a system failure in the wake of a massive earthquake and tsunami, triggered an order for hundreds of people to stay indoors, said Chief Cabinet Secretary Yukio Edano.

Tokyo Electric Power Co. said radiation levels at Unit 3 were 10.65 microsieverts, significantly under the 500 microsieverts at which a nuclear operator must file a report to the government.

The blast follows a similar explosion Saturday that took place at the plant’s Unit 1, which injured four workers and caused mass evacuations.

More than 10,000 people are estimated to have died in Friday’s twin tragedy that has caused unimaginable deprivation for people of this industrialized country that has not seen such hardships since World War II. In many areas there is no running water, no power and four- to five-hour waits for gasoline. People are suppressing hunger with instant noodles or rice balls while dealing with the loss of loved ones and homes.

“People are surviving on little food and water. Things are simply not coming,” said Hajime Sato, a government official in Iwate prefecture, one of the three hardest hit. “We are only getting around just 10 percent of what we have requested. But we are patient because everyone in the quake-hit areas is suffering.”

He said local authorities were also running out of body bags and coffins. “We have requested funeral homes across the nation to send us many body bags and coffins. But we simply don’t have enough. We just did not expect such a thing to happen. It’s just overwhelming.”

Sato said local authorities may ask foreign funeral homes to send supplies.

The pulverized coast has been hit by more than 150 aftershocks since Friday, the latest one a 6.2 magnitude quake that was followed by a new tsunami scare today. Abandoning their search operations, soldiers told residents of the devastated shoreline in Soma, the worst hit town in Fukushima prefecture, to run to higher ground.

Sirens wailed and soldiers shouted “find high ground! Get out of here!” Several uniformed soldiers were seen leading an old woman up a muddy hillside. The warning turned out to be a false alarm.

“This is Japan’s most severe crisis since the war ended 65 years ago,” Prime Minister Naoto Kan told reporters Sunday, adding that Japan’s future would be decided by its response.

On Sunday, search parties arrived in Soma for the first time since Friday to dig out bodies. Ambulances stood by and body bags were laid out in an area cleared of debris, as firefighters used hand picks and chain saws to clear an indescribable jumble of broken timber, plastic sheets, roofs, sludge, twisted cars, tangled powerlines and household goods.

Helicopters buzzed overhead, surveying the destruction that spanned the horizon. Ships were flipped over near roads a half mile inland. Officials said one-third of the city of 38,000 people was flooded and thousands were missing.

According to officials, more than 1,800 people have been confirmed dead — including 200 people whose bodies were found Sunday along the coast — and more than 1,400 were missing in Friday’s disasters. Another 1,900 were injured.

But police in Miyagi prefecture say 10,000 people are likely dead in their area alone. Miyagi, with a population of 2.3 million, was one of the hardest hit areas.

“I’m giving up hope,” said Hajime Watanabe, 38, a construction industry worker.

“I never imagined we would be in such a situation” Watanabe said. “I had a good life before. Now we have nothing. No gas, no electricity, no water.”