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WEST, Texas (CNN) — Walls warped or blown off entirely, even ones made of brick. Roofs sunken in, if they are still visible at all. Garage doors lying in yards.

And, at the center of it all, a crater nearly 100 feet wide and 10 feet deep.

On Tuesday, the devastation from last week’s explosions at a West, Texas, fertilizer distributor became more eerily apparent as officials offered new details and opened more roads around the town’s hardest hit areas.

While the blast’s lethal power was clear, many other questions remain.

Why did a fire start in the facility, which had shut down to workers for the day? How did that fire spark the massive explosion that tore through the northern part of town — killing 14 people, including nine first responders, and injuring hundreds of others? hat, if anything, could have been done to prevent the tragedy?

So far, investigators have eliminated the possibility that natural causes started the fire, but they haven’t gone beyond that.

When not funneling in and out of the command center at West High School, federal, state and local officials spent Tuesday outside using shovels to methodically search for clues.

Assistant State Fire Marshal Kelly Kistner said investigators were starting in the least-damaged areas, hoping to determine the heat source or material that ignited the fire.

Residents of this tight-knit town of 2,800, meanwhile, tried to get back to normal, though the explosion is never far from their minds.

At the Pizza House on Oak Street, waitstaff and locals discussed the state of their homes while drinking their beers, trying to figure out how to deal with the fact their once quaint farming town now resembled a war zone.

Even so, on Tuesday — two days before President Barack Obama and first lady Michelle Obama head to Waco, about 18 miles south, for a memorial service at Baylor University — there were also sounds of a town moving on.

While some stood motionless outside their ravaged homes, others kept busy sifting through what remained. Power tools buzzed, and trailer loads of debris were trucked away.