There is no silver bullet, unfortunately, even if you can move them (These are laterals, not pivots?). Weighing the tires down probably won't help. Once the spans start resonating, it's game over. Perhaps with a lateral one thing you could do would be to put cement blocks under the spans in a parking position and attach cables to the underside of the V jacks in the center of each span to keep them from starting to rock. The towers would stay put in the span wouldn't start rocking. Would not need any tension on the cables really. They would just be there to absorb some of the energy.
A little over a year ago, high winds took down nearly 200 pivots across southern Alberta. Very few laterals here. These pivots were parked in all kinds of orientations. One of my neighbors had 10 machines tip over. Ours happened to be parked into the wind direction, so none of our machines were affected on that occasion. However despite our careful parking, this spring we had strong winds that were 90 degrees from the normal wind direction, and the way one pivot was parked near a hill, the hill funneled the wind just right that it took a single span and twisted it. Didn't collapse, but it bent the steel where the pipe attaches to the legs. Crazy to think about the physics involved! $17k later some new pipes were installed and the span is rebuilt. sigh. And don't get me started on insurance for pivots. Insurance companies just don't understand pivots at all.
You farming up in the Galilee region? Looks like the Hula valley to me in the pictures. What direction do your winds come from? I always enjoy driving through northern Israel seeing all the farming and love to see the pivots and laterals!
