Extreme weather appears to be a factor in the fatal collapse of a wall Friday night at an Amazon warehouse in Baltimore. Two workers were killed in the incident at the online retailer’s southeast Baltimore fulfillment center, which occurred during a severe storm that tore roofs of apartment buildings in the area and caused a ceiling to collapse at a store, injuring three people.

Amazon said the two workers who were killed were employed by an external company.

Weather services report that Baltimore experienced an EF-1 tornado that night along with microbursts - intense small-scale downdrafts produced by a thunderstorm or rain shower.