wind arrows

Occupying a shoreline site on the San Francisco Bay,  Wind Arrows is a 35-foot tall aluminum flagpole fitted with 26 angled horizontal arms attached at 1-foot intervals. Sailboat wind indicators are mounted at the tip of each arm.  The indicators graph wind shear - the way layers of moving air change direction with height.

 Because our bodies feel the pressure of a relatively small section of wind, we often assume that the wind flowing above us is fairly uniform in direction. In fact, wind is often highly stratified, and can be blowing at right angles to itself within 20 feet of vertical distance.