The Sukka used for the Misva on Sukkot must be covered with proper Sechach, which must be comprised of materials that have been detached from the ground, such as wood or branches. The question arises as to whether a Sukka remains valid if snow falls and accumulates on top of the Sechach, or if the snow freezes and forms a layer of ice on top of the Sukka. Does the layer of snow or ice covering the Sechach invalidate the Sukka, which is now covered by something which had not grown from the ground?
The Ginat Veradim (Avraham Ben Mordechai Halevi, Egypt 17th century), in one of his responsa (4:7), writes that a Sukka does not become disqualified if it is covered by snow or ice. He explains that since snow and ice naturally melt, and are not permanent, they do not form a Halachic "Ohel" (tent) that could disqualify the Sukka. He proves this point by noting that if one would form a tent out of snow or ice, and a dead body is situated inside the tent, other people in this tent would not become Tameh (ritually impure), because the structure does not qualify as a Halachic "Ohel." By the same token, a layer of snow or ice would not affect Sechach, since it is temporary and will eventually melt.
Accordingly, Hacham Ovadia Yosef, in his Hazon Ovadia – Sukkot (p. 38), writes that one may use a Sukka covered with snow or ice, and the Beracha of "Le’sheb Ba’sukka" may be recited. Although the Aruch Ha’shulhan (Rav Yechiel Michel Epstein of Nevarduk, 1829-1908) writes that one should not recite a Beracha when sitting in a snow-covered Sukka, Hacham Ovadia ruled that one who wishes to recite a Beracha may do so.
Summary: If a Sukka becomes covered with snow or ice, it is nevertheless valid for use, and one may even recite a Beracha over such a Sukka.
