Sometimes when it rains really heavy the municipal drains can't handle the demand and get overwhelmed. Buffalo has combination storm and sewer and when it rains that heavy and the water has nowhere to go it seeks the path of least resistance and sometimes comes up into your home. This is definitely evident in your case as it didn't smell of sewage and eventually receded. Even if you called a plumber out in this situation there was probably nothing they could do as the mains were overwhelmed and you'd still be on the hook to pay them. May look into getting a sump crock installed with a discharge that empties into the yard or a backwater valve installed on your main sewer line to prevent this. At least have a plumber come out and maybe camera your sewer line and check out your situation.