Cessna Citation Mustang (C510)
Air Traffic Control Fully Certified
Air Traffic Control Radar 6
Situational Awareness; Workload
ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Issued New Clearance
Human Factors; Staffing; ATC Equipment / Nav Facility / Buildings
A Cessna 510 was descending for PIH. I issued him 10000 feet and failed to notice that there was another 11000 feet area on his route. I was busy with multiple other traffic situations and DIJ departure/arrivals and didn't see that the C510 was in the 11000 feet area until he was already several miles inside it. The Terrain Alert Volume alert was not triggered that I saw. At that time; I issued the C510 the airport position; and he reported the field in sight; and was cleared for the visual. [I] recommend having a D-side; double check route before issuing descent clearance.
ZLC certified professional controller reported issuing descent; which put aircraft into a subsequent higher MVA.