Storm flap
A storm flap is a piece of fabric or other material that is attached to the front of a coat or jacket to cover and protect the main zipper or other fastening. Storm flaps are often found on raincoats and other outerwear, and are designed to help keep water out and keep the wearer warm and dry. They are typically positioned vertically along the front of the coat, and are often secured with buttons, snaps, or other fasteners. Storm flaps can also be found on the back of some coats and jackets, and are used to provide additional protection against wind and rain.
"I was really glad I had a storm flap on my raincoat when I got caught in the downpour on the way to the store. Without it, I might have ended up looking like a drowned rat, which wouldn't have been a great look for my Zoom meeting later. Instead, I arrived at the store looking stylish and ready to grab my groceries in style."