The root ᴹ√BAR appeared in The Etymologies of the 1930s, where its original sense was probably “raise” but the basic root gained the added sense of “uplift, save, rescue” (Ety/BAR). The basic root included derivatives like ᴹQ. varna “safe” and ᴹQ. varya-/N. beria- “to protect”. But it seems it also had several extensions as in ᴹ√BARAD or ᴹ√BARATH with the meaning “lofty, sublime” and ᴹ√BARAT which was the basis for the word N. barad “tower” (Ety/BARAD, BARAT, BARATH).
Tolkien mentioned this set of extended roots in later writings (date unclear, but probably the late 1950s or early 1960s) along with a fourth extension √BARAS, all having to do with “great height combined with strength, size, majesty” (PE17/22-23). √BARAT was still the basis for S. barad “tower”. The roots √BARAD and √BARATH were respectively the basis for Q. Varda and S. Elbereth (< Elen-barathī) as they had been in the 1930s. The new root √BARAS had derivatives tied to cliffs, as opposed to the 1930s where ᴹ√BARAS was an (unrelated) root having to do with heat (Ety/BARAS).
There was no mention of the base root √BAR in later writings, so it is unclear whether it retained the meaning “save”. In addition, there were certain phonological problems in the derivation of Elbereth from √BARATH in Sindarin that were not present in Noldorin (where frequently ei > e in polysyllables), and this word may have been transferred to the root √BER “marry”; see the entry on Elbereth for further details.