What does the cryptic crossword clue "It may be so wet and lonely in US park with geysers (11)" mean?

The wordplay uses an anagram. anagram of SO + WET + LONELY = YELLOWSTONE The answer is YELLOWSTONE.

It may be so wet and lonely in US park with geysers (11)

Daily Mail Cryptic #16595 | 29 Across | 2021-06-10 flower