Published: Jun 06, 2013 3:44 PM EDT

LEE COUNTY, Fla.- A fire inside a North Fort Myers Walmart forced customers and employees to quickly evacuate in to the rain. It happened shortly after 2:00 p.m. down Pine Island Road.

Fire crews believe lighting struck the outside electrical unt and started a fire inside the back electrical room.

One woman was shopping with her daughter when they were evacuated.

"All of the sudden, we just heard a rumbling sound and then the lights started to flicker on and off, on and off. And I hollered at her, and said the emergency power will come on, and then the door alarm came on, and was ringing in my ear. And then employees went isle to isle, yelling at everyone to get out because there is a fire in the back of the store," said Patricia Fitch.

Fire crews say the blaze stayed in the back room. Crews are working to clear out the heavy smoke that filled the entire store.