Trick for getting a frozen mill to spin:
Get some headlamps and put 'em across the diodes: Two from two AC phases to negative, one from the third phase to positive. (Switch 'em around after a few minutes if it hasn't come free yet, so different sets of coils get the doubled current.)
This will put a bit of DC current through the coils and warm up the stator with a few watts of dissipation, which may melt off the ice between it and the rotors after a bit.
If the rotors are freed from the stator the remaining ice near the axle should break off. Once it starts spinning again (or rocking) it's time to remove the lamps - and you may have to unhook 'em occasionally to see if it's come free yet: The current will produce some cogging. If it starts rocking but won't spin yet you can try switching which phase is + to run it back-and-forth as a stepper motor and try to knock more ice loose.
With continued rotation (or other motion such as rocking with gusts) it will tend to shed the stuff on the blades. Vibration from the imbalance once it spins will shake more loose. Even without the yaw tracking you should be limping along enough to pass cutin.
The leverage should break the ice free on the tail pivot and the vibes and tail torque eventually break the ice free on the yaw bearing and you're back in full production.
At least that's how I hear it works. I trust others with experience will confirm or correct this. (Especially if it's dangerously wrong. B-) )
If it doesn't work all you're really out is the precious battery power you used to light the inefficient lamps and heat the stator.