Q. A woman that lost lo-aleynu her father to the pandemic, and is afraid of going to the mikvah, can she tovel (immerse) now that the days are warmer in a lake or the ocean?
A. Poskim beware women to immerse in a sea or lake when it can be avoided. This is due to concerns that a woman immersing at a beach, is likely very conscious of being seen and is plausibly rushing the tevilah and may not do it properly. Also since the tevilah is done at night, in the dark, it is difficult to supervise properly. It is also difficult to find a woman to supervise the immersion, and tevilah without supervision is invalid. On the onset, the husband should not supervise his wife’s tevilah.
Another reason is, that it may be difficult to avoid sand or mud from becoming embedded in one’s toes. (See Binas Adam 24, Shiurei Shevet Halevi 198: 33-42, Poseach Shaar 23: 28. Pischei Halochos p. 388.)
Horav Shlomo Miller’s opinion is that in need situations, it is permitted to tovel in an ocean or lake. However, another woman must accompany her there to ensure that her entire body with all her hair is properly immersed in the water. It is worthwhile for her to go into the water while wearing sandals or Crocs, which should be removed before she immerses. to avoid any chatzitzah adhering to her feet. She should also not be standing on them during the tevilah.
Rabbi A. Bartfeld as advised by Horav Shlomo Miller Shlit’a