597. Lost in the Desert

Shabbos 2:21

If all the residents left their courtyard for another courtyard and while on the way one of them – we don’t know who – left the group and entered a third courtyard, where an avalanche fell on him, in such a case we do not remove the debris on Shabbos. Since the residents left their original place, it is no longer a given that there is a Jew among them, therefore we assume that whoever left the group was one of the majority. Therefore, if the majority of residents were Jewish and one person left the group for another courtyard after they left their original place, if he is covered by an avalanche, we would clear the debris on Shabbos.

Shabbos 2:22

One who is traveling in the desert and doesn’t know what day of the week it is should count six days and treat the seventh day as Shabbos, complete with kiddush and havdalah. Every day - even the day on which he recites kiddush and havdalah - he is only permitted to earn enough to survive. He may not do any work more than this because any day might be Shabbos. If he knows that it’s the eighth day or the fifteenth day of his trip, he is permitted to work on that day because he knows that he didn’t leave on the Shabbos but on the other days he may only do enough to survive.