ATF investigators say the flying debris on Sunday and Monday made it difficult for them to do a lot of work as they still look for the cause and origin from Saturday's massive fire.
It was still windy Tuesday but no glass or debris was falling to the ground. As a result, today has been ATF investigators' most productive day yet.
For the first time since the fire Saturday, ATF investigators were able to get into the Younkers Building, entering near where the old tea room would have been.
Investigators were also able to use forensic mapping technology from the ground.
All of this work was possible because the damaged EMC building has been patched up making the scene a lot safer.
Dennis Christy, a manager at EMC insurance has had a view of the old Younkers Building from his ninth floor office for years.
He never dreamed of seeing it like this.
"You see a collapsed shell of a building that was a landmark for Des Moines,” said Christy.
Christy is one of the few employees with a view of the scene from floors seven through nine.
"First thing this morning, everyone was taking a look," Christy told Channel 13 News.
Floors seven through nine have the most exterior damage. Many of the broken windows are now covered with wooden boards or film like material.
Employees who would have had a view of the scene from lower floors have been moved to other parts of the building, and may be there a while.
"It will take months to get this building back to where it was,” said Lisa Hamilton, the VP of Corporate Communications for EMC Insurance.
While the repairs have got EMC back to work, they have also helped ATF investigators.
"Our agents were able to make entry into the building on the west end,” said John Ham, public information officer for the ATF.
Forensic mapping technology will help combine the evidence with burn patterns and data they analyze from viewing video sent in by the public.
"They can tell a lot from how the fire is behaving, what the flames are doing, and what the structure is doing from those videos,” said Ham.
Investigators continue to ask the public for any videos or still photos from the fire.
So far, Des Moines Police have collected about two dozen videos and photos.
Over the past three days, investigators have interviewed over one hundred people from people passing by to those working in the building Friday.
Still, no potential cause has been ruled out.
The ATF expects to know the cause in about one week.