A small army of workers set to work Saturday to replace the estimated 200,000 square metres of windows shattered by the shock wave from a meteor that exploded over Russia's Chelyabinsk region.

The astonishing Friday morning event blew out windows in more than 4,000 buildings in the region, mostly in the capital city of the same name and injured some 1,200 people, largely with cuts from the flying glass.

Forty of the injured remained hospitalized on Saturday, two of them in serious condition, the state news agency RIA Novosti reported, citing the regional health ministry.

Meteor, meteoroid, or meteorite?

Small pieces of space debris — usually parts of comets or asteroids — that are on a collision course with the Earth are called meteoroids. When meteoroids enter the Earth's atmosphere they are called meteors. Most meteors burn up in the atmosphere, but if they survive the frictional heating and strike the surface of the Earth they are called meteorites.

Regional governor Mikhail Yurevich on Saturday said damage from the high-altitude explosion — estimated to have been as powerful as 20 Hiroshima bombs — is estimated at $33.2 million Cdn. He promised to have all the broken windows replaced within a week.

But that is a long wait in a frigid region. The midday temperature in Chelyabinsk was minus –12 C, and for many the immediate task was to put up plastic sheeting and boards on shattered residential windows.

More than 24,000 people, including volunteers, have mobilized in the region to cover windows, gather warm clothes and food and make other relief efforts, the regional governor's office said. Crews from glass companies in adjacent regions were being flown in.

Divers search for meteorites

In the town of Chebarkul, 80 kilometres west of Chelyabinsk city, divers explored the bottom of an ice-crusted lake looking for meteor fragments believed to have fallen there, leaving a six-metre-wide hole. Emergency Ministry spokeswoman Irina Rossius told Russian news agencies the search hadn't found anything.

Police kept a small crowd of curious onlookers from venturing out onto the icy lake, where a tent was set up for the divers. 

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A circular hole in the ice of Chebarkul Lake where a meteor reportedly struck the lake near Chelyabinsk on Friday. (Associated Press)

Many of them were still trying to process the memories of the strange day they'd lived through.

Valery Fomichov said he had been out for a run when the meteor streaked across the sky shortly after sunrise.

"I glanced up and saw a glowing dot in the west. And it got bigger and bigger, like a soccer ball, until it became blindingly white and I turned away," he said.

In a local church, clergyman Sexton Sergei sought to derive a larger lesson.

"Perhaps God was giving a kind of sign, so that people don't simply think about their own trifles on Earth, but rather look to the heavens once in a while."

In Chelyabinsk, university student Ksenia Arslanova said she was pleased that people in the city of 1 million generally behaved well after the bewildering flash and explosions. 

"People were kind of ironic about it. And that's a good thing, that people didn't run to the grocery store. Everyone was calm," the 19-year-old architecture student said. "I'm proud that our city didn't fall into depression."