Alaska Airlines Flight No: AS 634 Seattle to Las Vegas - Reg: N323AS - B737-900. The aircraft was descending towards Las Vegas when the crew reported white smoke in the cabin and loud noise. After landing the crew advised the smoke had dissipated, however, still requested emergency services to check the aircraft. The aircraft vacated the runway on the adjacent taxiway, emergency services checked the aircraft that subsequently taxied to the apron. The aircraft was still on the ground 4 hours after landing. If there are any further updates these will be published.