> uncertain and difficult and not likely to last long
> difficult or uncertain
> unable to balance very well
https://dictionary.cambridge.org/dictionary/english/rocky
The parent to your comment is correct, as are you about the specific reference in this case.
The etymology of the Rocky Mountains is unrelated to either:
> The Rocky Mountains were so called by 1802, translating French Montagnes Rocheuses, first applied to the Canadian Rockies. "The name is not directly self-descriptive but is an approximate translation of the name of the former Native American people here known as the Assiniboin .... The mountains are in fact not noticeably rocky"
https://www.etymonline.com/word/rocky