The wind flag lie that made me triple check my pick radius

I was setting steel on a hospital roof in Des Moines last fall and the wind flag at the top of the tower showed a steady 12 mph from the west. My spotter kept saying it felt like a stiff gust coming off the parking garage, but I waved him off since the flag looked calm. Halfway through the lift, a 25 mph gust caught the load sideways and swung it into a guardrail, dented a brand new beam and made the safety guy go pale. What changed my mind was the owner pulling me aside and pointing out our flag was behind a parapet wall, so it only caught the sheltered air, not the real wind. Now I watch the trees and the water tower across the street before any pick, and I ask my spotter to call every gust, no matter how small it feels. Has anyone else found a better way to judge wind when your tower flag is blocked?

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phoenix_carter19d agoMost Upvoted

Whoa, hold on, the flag wasn't just blocked, it was reading the wind that was bouncing off the wall, so it was actually showing you the wrong direction too, not just a calm version.