Ropes magically eject from your wand and keep the door open. Perhaps that action was a little too cautious. Nevertheless, your sister was free to leave the cage whenever she had the ability to move again.

The warming spell brings a source of heat to your sister. Icicles that were clinging onto her dark brown hair gradually begin to melt because of the heat. However, you sister's teeth are still chattering and her body still shivering. It is still too cold her her to be facing the arctic weather with just a single charm to keep her warm up to a certain point. "L - L - Lou - Louise," she manages to speak.

As for where you need to go, well, following the wind worked last time, didn't it? Though not as strong as before, it was still blowing south.