I was not home when this occurred, but got home shortly after the incident. My three roommates were all in my kitchen on the first floor which views directly into our backyard and onto our wooden deck. At approximately 11am on 3/18/21 they saw a man wearing all black with a hood up walk up the steps to our deck, grab my bike, and walk down towards the gate. By the time they realized this man had grabbed my bike, they opened our back door and yelled at him, getting only a muttered respsonse back, before he opened the back gate and quickly rode off down the alley. They are unsure how he got onto our deck because our entire yard is fenced in with a tall wooden fence and locked gates in the front and back. We believe he must have climbed over our or our neighbors fence to get into our yard before snatching my bike. My roomates described him as a shorter male with a hooded puffy jacket, and black sweatpants with three orange stripes going down the side, like adidas track pants.