I had no ideal that a semi could flip a bike. I have been knocked sideways, but always recovered. Is the worst wind when they are coming towards you or passing?
Passing in the left lane. I was in the right.
7-10mph head wind, open farmland, on top of an overpass headed directly into the wind, double metal guard rails in a funnel shape on the upwind end of the bridge. Sooooo, 1) soft breeze is pushed up the earthen embankment taking the road up to overpass level. 2) doubled guard rail functioning as a waste high wall wind could not go over as the road was already going up, so the pressure of the overhead air (roughly 14.6959 pounds per square inch) preventing the rise of the ground air mass caused the ground air mass to significantly increase speed. That's all common if you've ever studied meteorology, aerodynamics, gaseous-dynamics, etc. Simply physics 99.9% of people know absolutely nothing about. Then, the bike had full aero plastic, aluminum bags, and tall visor, so it was shaped like a kit from the front view, and like a symmetrical air foil from a top view. Plus, a day cab is a flat bottom edge with sloped sides and a climb towards the rear for aerodynamic fuel savings, so air mass is pushed sideways, which is the force you've felt. Actually, 4 times the force you felt if the truck that blew you around was doing the speed limit. Finally, the bike was fully dressed and just over 300 pounds, I imagine significantly lower mass motorcycle than the one you experienced the rocking, so inherently more easily victimized. The massive wind from the truck's stupid speed, which it achieved with a 7-10mph headwind was kept at speed by the mass of the truck when it hit the increased windspeed at the far end of the bridge (I've revisited the wreck location and measured air flow, 9-12mph no traffic away from wedging obstacles, 37-45mph on the bridge with no traffic due to wedging obstacle aerodynamics). I've also measured wind speeds of trucks passing at legal speeds, and usually about the same as road speed. It slowed pretty quickly, I've been told, but by that time the damage was already done. However, when you add the 30-40mph headwind to the 130+ sidewind, you are at a 160-170mph wind hitting the bike. That's a Category 5 hurricane equivalent wind speed, the ones with the absolute highest, most dangerous winds. That's the best I can figure. Worse, the winds of the nose often generate tornado-like vortices moving aftwards down the sides of a solid walled trailer. I've seen that doodling along the highway with smoke pots.
Once the bike's tires were off the ground, the cab airflow of the truck leaned it over, and with the bodywork actually forming a symmetrical airfoil, up she went when that 160mph wind blast passed under her. Best I can figure the physics.
That is why that 250 stays in the garage and my current bike for long highway rides on divided roads with high speed limits is a naked Nighthawk 750. Not even a windshield, just a luggage rack, and some day a top case once I complete the total LED light conversion so I can run 3 LED H4 replacements.