Stall AOA change due to Mach
The stall angle of attack does not start to increase with Mach until above about .3M, which in the "shortly after takeoff" range is about 200 knots. Obviously, the indicated equivalent to that goes down with altitude.
So, you have to be maneuvering with a high enough g load to have a fairly high angle of attack, then be in the right kind of icing conditions for the vanes to freeze in position, then increase your Mach.
If crews are made aware of it (and they certainly should be made aware), and they see the warning signs (alpha prot on airspeed indicator in an unusually high place), then they can take preventive measures : Don't go any faster, and turn off two ADRs to disable the alpha protect.
AF447: >>ALT II (b) killed 447.<<
ALT 2 b, didn't kill them. They killed themselves. More specifically, the PF in the right seat killed them all by not being able to fly straight and level without the flight director.