Yes, klondikes is a Scrabble word!

Noun

1. A region in northwestern Canada where gold was discovered in 1896 but exhausted by 1910
2. A form of solitaire that begins with seven piles of cards with the top cards facing up; descending sequences of cards of alternating colors are built on these piles; as aces become available they are placed above the seven piles; the object is to build sequences in suit from ace to king as the remaining cards are dealt out one at a time