sewer smell outside house / no trap or drain at front of house

Last night after the heavy rain, I stepped out of our house (1st floor) and smelled a light sewer smell. It’s the first time I’ve smelled it. Our basement is always dry, knock on wood, haven’t had issues with backup in basement. What could be causing this smell? Could it be us, or one of our neighbors? BTW, we don’t have one of those upside down U-shaped / candy cane shaped traps on the outside of the house like I see many/most houses and apartment buildings have. Should we?