Date: 201604
Local time of day: 1201-1800
Location: LAS.Airport, NV
Weather elements / visibility: Turbulence
Light: Daylight
Aircraft: B737-800
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class E L30
ATC / advisory: TRACON L30
Reporter organization: Air Carrier
Reporter function: Pilot Not Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Anomaly: Flight Deck / Cabin / Aircraft Event Illness / Injury; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Attendant; Person Flight Crew
When detected: In-flight
Result: Aircraft Aircraft Damaged
Contributing factors: Procedure; Weather
Primary problem: Weather

Narrative: During descent into LAS on the KEPEC3 Arrival we encountered Severe Turbulence over KEPEC waypoint as we were descending between 13000 ft down to approximately 7000 ft. I advised Approach Control immediately and suggested they keep aircraft that were behind us above 13000 ft and away from that geographical area. The winds were gusty from the Southwest and it appeared to be terrain induced over the Ridge-line southwest of the Airport. Once below 7000 ft the ride became mostly light to moderate chop to turbulence. Winds were gusty at the surface and we landed on Runway 25L. I called the Flight Attendants before landing and made sure that all Passengers and Crew were ok. Severe Turbulence encounter was entered into the Logbook. Due to the gusty conditions at the Airport; I anticipated a bumpy ride and I had the Flight Attendants prepare the cabin early prior to starting down; so they were seated and strapped in prior to the encounter with the Severe Turbulence. We had no warning of adverse rides from ATC/Approach Control; who told me; we were the first ones through that area in over an hour.  After landing in my debrief with the Flight Attendants; I was told that even though the FA's were strapped in; they were physically lifted off their seats and slammed back into the seat bottoms multiple times. Aircraft was eventually removed from service for inspection. Probably the most extreme ride in my over 30 years of Aviation.In the many times I have flown into the LAS area; I've encountered rough air almost every time coming in from the West. It is a 'Norm' of the LAS Arrival.  I have found the worst part of that descent is associated with this same geographical area around KEPEC Intersection. My suggestion as an Aviator would be to modify the Arrival's lateral profile and descent to keep aircraft clear of this point. I would suggest a change in routing from around Waypoint CLARR to direct NIPZO; or IPUMY if you have to; and avoid the descent and lateral leg from SKEBR to KEPEC to IPUMY all together. The ridge line is so close to that ground track that I believe it puts Aircraft; Crew and passengers too close to the potential for significant Turbulence encounters.




Synopsis: B737-800 Captain reported severe turbulence and injuries to flight attendants; even though they were strapped in; during descent on the KEPEC3 Arrival to LAS. He suggested that the arrival be revised because it is always turbulent in that area when the winds are from the southwest.