Safety reminder. We did a job yesterday maybe 4/12 roof pitch. My guy gets on roof to check pipe boots and a quick look over as she is selling house. He goes maybe 10' and slips. It was a shingle over and the shingles slid loose. It was on a 10' x 10' area and the shingles were high nailed. The wind must have lifted the tabs enough so that the heads ripped through but the shingles were in place and you would never know. In your next safety meeting this is a good reminder for your employees. He could've twisted an ankle, sprained a wrist or at worse fallen off roof or a skylight