Sewage came up through basement sink in storm

Pretty much what the title says, we have a closet in the basement that has all the water shutoffs and a sink only connected to cold water. We had a weird smell in our laundry room area and basement and finally opened this closet and realized sewage had come up through the sink, super gross. Anyway, I am receiving conflicting advice ranging from call a plumber immediately to just ignore it unless it happens again. Any thoughts?

As background we have only been in this house for 8 months, this is the first time this has happened to us and previous owner had a rug in the basement (we obviously need to remove now) and his kids played down there so I'm guessing this had not happened often if at all in the past.

Thanks in advance for your responses!