By SAM METZ and BRIAN MELLEY SOUTH LAKE TAHOE, Calif. (AP) — Ash rained down on Lake Tahoe on Tuesday and thick yellow smoke blotted out views of the mountains rimming its pristine blue waters as a massive wildfire threatened the alpine vacation spot on the California-Nevada state line. Tourists ducked into cafes, outdoor gear shops and casinos on Lake Tahoe Boulevard for a respite from hazardous air