My first guess would of been the oil pump was not working properly. You said the coolant wasn't frozen but very hot that means the thermostat wasn't stuck. With the temperature at 10 below, Even with no water and antifreeze flowing through the water jackets the frigid air blowing from the fan should of help reduce the engine temperature enough to prevent the pistons from total melt down. How was the engine oil level? I don't buy the frozen radiator deal, It just doesn't seem right to me.