Can one walk on snow on Shabbos when there is another route one can take?

Question

In OC 320, the Shulchan Aruch discusses the prohibition of crushing on Shabbos. In §13, he rules:

דורס שלג ברגליו ואינו חושש:

One can stomp snow with his feet and not be concerned.

The Mishnah Berurah there (§39) explains:

ואף אם השלג נימוח וזב עי"ז לית לן בה כיון דהוא אינו מתכוין לזה והט"ז כתב דכיון שהוא דבר שא"א ליזהר בזה לא גזרו ביה:

Even if the snow will be smoothed or melt through this, there is no [concern] to us in it, since he doesn’t intend for this. The Taz wrote that since it’s something which one cannot be careful about, they didn’t decree on it.

To quote the Taz (DH biraglav v’eino chosheish) in full:

נראה דאע"ג דא"א שלא יהי' נימוח והוי פסיק רישיה מ"מ לא גזרו בזה כיון דא"א להזהר מזה בימות החורף דכל הארץ היא כך מלאה כפור וגליד והמנעלים הם לחים ונימס השלג שם:

It seems that even though it’s impossible that it won’t be smoothed out, and it would be a Pesik Reisha [it will definitely occur if you do this action], nevertheless they did not decree on this, since it’s impossible to be careful about this in the winter, when the entire ground is full of frost and ice, and shoes are wet and melt(?) the snow there.

According to the Mishnah Berurah, that the leniency is that it’s unintentional, does this leniency apply when there is a path that’s not covered by snow? Do we say that since one doesn’t have to trample the snow, one should avoid it (or perhaps going on the snow anyway might indicate that one intends to crush the snow)? Or once they didn’t decree in the general case, they didn’t decree in any cases and it should always be allowed?

According to the Taz, that the leniency is because it’s impossible to avoid the snow, does that mean that when it is possible to avoid the snow, one is liable for crushing it? Or, once again, once they didn’t decree in the general case, they didn’t decree in any cases and it should always be allowed?

Answer 1

There is a Machlokes Between the Aruch (Rav Nosson MiRoma 11th century among other rishonim) and Ri (Rabbeinu Yitzchak MiDanpierre 12th century among other Rishonim) in Tosfos throughout Shas whether פסיק רישא דלא ניחא is permitted on Shabbos or not, see Tosfos Shabbos 103a "Lo tzricha". Loosely translated as "one who causes a Melacha to be transgressed without any want or gain from that Melacha," for example walking past a sensor light when there is sufficient light to see clearly. Or over here treading on the ground when snow is in the way and one has no gain in crushing the snow when he treads on the ground. But CYLOR which specific cases this applies to as the cases can be vast and complicated.
Altogether there are 3 main opinions:

1. The Mishna Brura fits according to the Aruch (Tosfos Mesachraisa Kesubos 6a) Psik reisha Delo Nicha is permitted Lechatchila
   פירש בערוך דכל פסיק רישיה דלא ניחא ליה שרי ועיקר ראייתו מפרק כל התדיר (זבחים דף צא: ושם) אליבא דר"ש מזלפין יין על גבי האישים אע"ג דפסיק רישיה הוא דודאי מכבה הוא כיון דלא ניחא ליה בהאי כיבוי שרי
   for example when one pours wine libations over the fire on the Mizbeach this is permitted even though it causes the fire to go out which is normally forbidden he does not want the fire to go out or does not gain from it so hence permitted.
   So too here he does not care about the snow turning into water, so one can walk along the snow even when there is an alternative route like the Aruch, and thats why the Mishna Brura says
   לית לן בה כיון דהוא אינו מתכוין לזה

2. The Mishna Brura fits even according to the Ri in Shabbos 103b who says that Psik reisha Delo Nicha is forbidden for a Melacha Deoraisa for example fixing a kli by blocking a hole in the barrel with a towel permanently.
   But here since causing the snow to turn into water is only Ossur Miderabanan one is allowed to walk over on Shabbos when he does not care about the snow turning into water even when there is an alternative route because The Chachamim did not decree in a Melacha Derabanan (see Beis Yosef OC 320 who says melting snow is Nolad) that he does, when he does not want it or not gain from it
   דאותו תיקון מועט כמו . מיעוט ענבים דלא אסיר אלא מדרבנן לא גזרו חכמים כשאינו נהנה

3. But the Mishna Brura does not fit with the Ri Tosfos Kesubos 6b argues with Tosfos Shabbos 103b in the name of Ri and says:
   ההיא דמתיר ר"ש לזלף יין על גבי האישים איכא למימר דמצוה שאני וכן ההיא דאית ליה הושענא אחריתי איכא למימר דשרי משום מצוה..משום צערא פטור ומותר אבל אי לאו משום צערא היה אסור Even in an Issur derabanan we still need a reason Letzorech Mitzva or Bemakom tzaar to allow Psik reisha Delo Nicha for example eating berries of Haddassim to make them Kosher to put on the Lulav, so that one could add more Haddasim to his Lulav. He already has one hadas for which to do the Mitzva so he does not care to add another and for the sake of Hiddur Mitzvah we waived the decree.(see Koveitz shiurim Kesubos Siman 18).

So it could be the Taz like the opinion Tosfos in the name of the Ri in Kesubos 6a did not want to allow walking in the snow without a stronger reason like Tzorech Mitzva or Bemakom tzaar so only because there is snow everywhere and it is uncomfortable for people to stay inside and not go outside, we allow Psik reisha Delo Nicha walking in the snow because its an Issur derabanan case where the Chachamim were not Gozer, but if an alternative, reasonable route is availlable one should not tread across the snow needlessly.

But the Mishna Brura allows to walk across the snow even when one can go another way as its a Psik reisha Delo Nicha when doing an Issur derabanan Like both the opinions of the Aruch and the Ri In Tosfos Shabbos 103a.

See http://asif.co.il/?wpfb_dl=406 for a deeper analysis

Answer 2

No, they are not liable even if they have another path.

The prohibition to crush snow is only rabbinic in nature (see Beis Yosef OC 320 who says melting snow is Nolad) and in the case where the result is unintentional(because you don't want ice-cold water), it is permitted.