A sprinkler system malfunctioned at the Dickinson Walmart at about 3:50 p.m. Monday, causing employees and customers to evacuate after the fire alarm went off inside.

Firefighters cleared the scene for re-entrance after about 30 minutes. An unexplained pressure drop in the sprinkler system caused valves near the store’s main entrance to expel excess water, Dickinson fire marshal Deb Barros said.

A sprinkler system contractor was coming to the store at about 4:30 p.m. to investigate and fix the problem, Barros said.

Walmart managers and employees stood outside in rainy, windy conditions, waiting for the go-ahead to go back inside.

“It’s so cold, but at least it’s not snowing,” said Walmart photo center technician Chad Racine.

No items were damaged by sprinklers, according to multiple Walmart managers and employees.

Dickinson firefighters, police officers and ambulance service personnel responded to the scene.