The words with strong connotations in the passage are gloom, enveloped, stealthy, ominous, unearthly, dread.
Regarding the effect of the word "dread" compared to "fear," the correct answer is:
It has a more negative connotation than “fear.”
"Dread" suggests a deeper, more intense feeling of apprehension or anxiety, while "fear" can be more general and less intense.