Diablo Lake Diablo Lake can be visited along Highway 20 through the North Cascades. The water gets its deep aquamarine color from very fine rock particles that are created by grinding glaciers in the mountains above. Diablo Lake Scott2015-10-01T23:34:16-07:00July 15, 2006| Share This Story, Choose Your Platform! FacebookXRedditLinkedInTumblrPinterestEmail