When did 「ヤッホー」 become a popular greeting?


The etymology of the very casual greeting 「ヤッホー」 appears disputed and
undecided. Various theories and hypotheses have been suggested. This
[site](http://www.worldfolksong.com/calendar/japan/echo-mountain.html) lists
German, Hebrew, and 山伏 as possible sources. A lot of places claim it was a
mountain climbing term
([this](https://answers.yahoo.com/question/index?qid=20080720233045AAiorgu),
[this](https://dictionary.goo.ne.jp/word/%E3%83%A4%E3%83%83%E3%83%9B%E3%83%BC/),
and many others). My question is when did it become popularized among young
people as a fashionable greeting? When did become a thing in Japan? Where did
it start? Did it start among members of a subculture (e.g. various teen
subcultures in 渋谷/原宿)? I know the term has been around for at least 10, 15
years.




The word itself has been widely recognized for a long time as "something you
shout in the mountains". Even [novels written in the 1950's have examples of
ヤッホー](https://myokoym.net/aozorasearch/search?word=%E3%83%A4%E3%83%83%E3%83%9B%E3%83%BC).

In town, it may be used very occasionally as a humorous, unique greeting.
Well, sometimes people feel おはよう is too uninteresting and want to say
something different. I may have heard ヤッホー used in this way once or twice in
the last 20 years. However I don't think it has ever been "popularized among
young people as a fashionable greeting" in the 21st century. This is an old
word everyone knows since childhood, and as far as I know, there is no reason
for it to suddenly become a fashion. Theoretically, there may be a community
(e.g., fans of a singer) where ヤッホー is used as a popular greeting, but I am
not aware of such an example.

