Light Transport; Low Wing; 2 Turboprop Eng
Air Traffic Control Fully Certified
Distraction; Situational Awareness; Workload
ATC Issue All Types; Inflight Event / Encounter CFTT / CFIT; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Issued New Clearance
Human Factors
I had been working Arrival E and Arrival W combined during the beginning of an arrival rush. Aircraft were beginning to step on each other over 2 frequencies as the workload increased. Multiple aircraft also started to report icing in the weather which added to the frequency congestion. Another controller finally came back to split the Arrival West frequency. As that briefing was happening; I accepted a handoff from the P sector of Aircraft X. The controller verbally coordinated to me that the aircraft was direct the SEA065050 fix climbing to 3;000 feet. This is an abnormal route for our airspace which requires coordination with departure a; as well as sector 31. I was stepping Aircraft X up underneath arrivals on the GLASR arrival as soon as I could. At some point; I became preoccupied with the multiple Seattle arrivals and when I looked to climb Aircraft X further; he was already about to enter the 7;000 foot MVA area only climbing out of 6;200. I asked if he could maintain his own terrain/obstruction clearance through 8;000 and he replied negative. I gave him an immediate right turn to a 180 heading to get him out of the area and issued a climb to 15;000. Aircraft X was in the 7;000 MVA for a couple miles. Once above the MVA; I turned him back on course and gave the frequency change to sector 31.First and foremost; traffic management came over to me and said they tried to get me help to split the sector but that there wasn't the staffing. So I continued to work both sectors until relief was brought back in. Just because the board doesn't look like the volume of traffic is too difficult for one controller to work both sectors combined; doesn't mean the complexity of our airspace won't warrant the sector to be split.Stepping up aircraft from Paine field underneath arrivals on the GLASR arrival to SeaTac is cumbersome and takes attention away from other things that need to be done. This will be amplified once commercial service begins flying daily flights out of that airport. There are no procedures in place to handle the influx of this traffic and there will be more events like the one that just happened.
S46 TRACON Controller reported working a combined position; having to climb an aircraft underneath other aircraft and it entered a higher MVA.