552. Snow and Ice
In an introductory note to this chapter, the Kitzur Shulchan Aruch writes that most Jews are already familiar with the prohibited labors of Shabbos and that he is only addressing common situations with which people may not be familiar. Clearly, the laws of Shabbos constitute an area requiring much greater study than this email alone will allow. 80:13 A nursing mother may not express milk into a cup or a bowl to feed her child. She may, however, express some milk (into the baby's mouth - Mishnah Brurah 328:112) to encourage him to latch on and nurse. She may not express milk onto an injury for medicinal purposes unless there is some danger or great pain.
80:14 One may put congealed fat on hot food even though it will melt. Snow and hail may not be crushed by hand in order to turn them into water. (One may break off some snow or ice if he wants the thing itself even though some water may be exuded as a result of this - MB 320:32.) One may, however, put it in a cup of wine or water to chill it without concern that it will cause the ice to melt. In the winter, we must be careful not to wash our hands in water that contains snow or ice. If one does wash in such water, he must make sure not to rub it between his hands, which would crush it. One is allowed to break ice in order to wash in the water under it. One should try not to urinate into snow if not absoutely necessary. Similarly, one should try to avoid urinating on mud or soft dust.