Beech F90
Air Traffic Control Fully Certified
Situational Awareness
ATC Issue All Types; Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Issued New Clearance
Human Factors
I was working 2 sectors combined with 3 different frequencies. We just started using a temporary Tower nearby due to the fire fighting aircraft which makes operations a little bit more difficult due to the coordination required. It felt busy due to all the aircraft stepping on each other. A King Air F90 was descending and I assigned him 160. He requested lower and I assigned him 140 in a 150 MIA. It never flashed with terrain but once I realized the mistake I made I asked him if he had good visual with the terrain which he replied yes to. Then I told him to stop his descent and that I would have lower for him in one minute.
Enroute Controller; distracted by other than normal duties; issued an altitude below MVA requirement; correcting same quickly.