Looking at snow surfaces today ahead of the Thursday night "storm". Weak faceted recrystallized snow in northerly protected terrain on the snow surface has been well documented (and skiied/ridden). They involve metamorphism of the snow that already exists at or near the snow surface, owing to a temperature or vapor pressure gradient. They look small and angular...and new snow tends to bond poorly to them. See 1st photo below.

Both surface hoar and rime involve water vapor or supercooled water droplets being deposited onto the snow surface from the atmosphere. These events may be localized or regional in nature, but new snow bonds poorly with SH and surface facets and "it depends" with rime. See 2nd and 3rd photos below. Rime looks rounded and clustered...surface hoar look angular and beautiful.

I hope to get some reports tomorrow (Thursday) on how the snow surface has evolved...