Most of us have been in a 60km/hr gale, if only for a brief gust. It roars, it knocks down trash cans, it can make us stumble, but it isn't all that dangerous.
The force of the wind can be estimated by dynamic pressure, which is $1/2 \rho v^2$ for air density $\rho$ and velocity $v$. Given that $\rho$ is about 1.3 kg/m^3 the dynamic pressure at 60 km/hr is about 180 Pa, or 18 kg/m^2. This is just enough to push a person off balance.
Suppose there is a planet with a very thin nitrogen-based atmosphere at Earth-like temperatures. So thin that a Mach 2.0 wind (680 m/s, 2450 km/hr) would push with about the same dynamic pressure as our low-grade gale on Earth. This would require a density of only 0.00078 kg/m^2, about 25 times less dense than mars.
Such a planet somehow has supersonic storms from time to time. How would a low-density, high-speed wind feel like to an (anaerobic) person dressed in shirtsleeves? Could they reach out and touch the shock-waves? What would the wind sound like?
Are dust-storms lethal because sand and small debris picked up moves at the speed of a bullet? Would there even be sand or would it all get ground into extremely fine powder?
