Rules were made to be broken. In formal writing, your example might be considered questionable because it does not begin with an independent clause. However, you will regularly see sentences like this in published works of fiction, because they allow a more natural, conversational flow.
The same sentence could be written with a colon, but it would have a different "feel" to it. The problem is that dashes are also used to denote interruption, while colons are not. So with a dash, your sentence connotes a stream of consciousness, with the narrator abruptly generalizing from specific elements to Hawaii as a whole. With a colon, it connotes an itemized list summarized by the thought about Hawaii, a much more dry and academic style of writing. But if you want to be dry and academic, you probably want to recast the whole sentence (and move Hawaii to the front), so it doesn't really work with the colon.