The Phoenix Fire Department says it is possible a partial roof collapse to the rear of a Safeway broke a gas line and damaged the main electrical box, causing the store to catch fire.
The store was destroyed, but no injuries were reported.
More than 75 firefighters responded to a three-alarm fire at the Safeway near 35th and Northern avenues on Wednesday.
An employee had call 911 and when crews arrived no one was in the store.
Crews from the Glendale and Phoenix fire departments battled the blaze after it broke out around 6 p.m.
According to a release, crews made a fast aggressive attack on the fire and started conducting a search and rescue while clearing the store of patrons and employees.
During that time, a section of the roof collapsed, forcing firefighters to pull back their positions.
After an “all clear,” crews moved to a defensive strategy, meaning firefighters utilize numerous large water streams from elevated ladders. Crews also set up large hose streams to fight the fire and protect surrounding businesses connected to the burning store.
No other business were affected, the department says.
Firefighters continued extinguishing the fire at night and containing it to the store.
Phoenix fire Captain Rob McDade said it is possible a microburst in the area may have been a factor, but it is too early to determine an official cause.
According to the National Weather Service, a microburst is a localized column of sinking air (downdraft) within a thunderstorm and is usually less than or equal to 2.5 miles in diameter.
They can cause extensive damage at the surface and can be life-threatening in some instances.
A third-alarm fire normally sees at least 100 first responders at the scene.
Television footage showed the supermarket completely engulfed in flames with a huge plume of black smoke visible for miles over the city.
The lettering on the building could be seen falling off.
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