Officials in Edwardsville, Ill. Said rescuers face a huge challenge locating missing workers at an Amazon warehouse that partially collapsed in severe weather.

“It’s a total disaster,” Police Chief Mike Fillback said at a press conference on Saturday morning.

Fillback has confirmed that at least two people are dead, and rescue efforts are proceeding slowly for the safety of first responders. “You have concrete and things are hanging,” Fillback said. “It’s very windy outside so things are unstable.”

Fillback said dozens of people were able to leave the scene without serious injury, although an exact number cannot be given as some were able to walk away unassisted.

Authorities will not speculate on the duration of the rescue operations, but the clean-up will not be completed anytime soon. “This will continue over the next few days,” said Edwardsville Mayor Art Risavy.

Amazon spokesman Richard Rocha called the situation a “devastating tragedy.”

“Our thoughts, prayers and deepest condolences go out to the victims, their families and all those affected. This is a devastating tragedy for our Amazon family and our goal is to support our employees and partners, ”Rocha said in a statement.