When a hurricane brings its winds inland, the fast-moving air hits terrain and structures, causing a frictional convergence which enhances lifting. Frictional convergence may be at least a contributing factor to tornado formation in hurricanes. The greatest concentration of tornadoes occurs in the right front quadrant of the hurricane. A number of theories exist about their origin, but in the case of Hurricane Andrew, severe damage was inflicted by small spin-up vortices that developed in regions of strong wind-shear found in the hurricane's the eye wall. The strong damaging winds of the hurricane frequently cover the smaller tornado paths, making the separation of their damaging effects very difficult.