Air Taxi Captain reported the left wing made contact with an object as the aircraft was taxiing from the ramp. The ramp was covered with snow; taxi lines were not visible and the ramp marshal was directing the procedure. After maintenance inspection the aircraft was cleared to remain in service. The Captain states the wing walkers need more training.

Narrative

This morning I took Aircraft X to ZZZ with cargo. The aircraft was parked in the north row at Company A; facing the building and narrow alleyway. The ramp had 1-3 inch snowdrifts; and all lines and markings were not visible on the Company A's ramp. During my preflight; I thoroughly inspected the wings while brushing them off; and no abnormalities were detected. After pulling out into the alleyway; I recognized the hazards of the taxi environment being a lack of visible markings; occasional reduced visibility from blowing snow; and less than perfectly clear flight deck windows. I removed 90-95% of the snow and ice from the windows with the brush and windshield heat; but some distortion remained. Without the lines to guide me; I did my best to taxi in the center of the lane; and follow the guidance of the marshalling crew. I scanned left; center; right continuously while taxiing at 1 kt. (very slow walk). There appeared to be an equipment rack on the left side of the alley that was going to be close to the aircraft; so I nudged the plane right approximately 6 inches. All marshallers continued to guide normally with no indication that I would hit that equipment. As I got closer to it; I still thought I was too close and deviated right another 6-12 inches. During one of my scans to the left immediately adjacent to the rack; I noticed a small amount of snow appear to fall off of that equipment. I did not feel an impact; and did not see the plane make contact with the equipment; and believed that the snow could have fallen due to wind or prop wash. As I made the right turn to proceed out of the alley; I did notice the Lead Marshaller shouting to the left wing walker and I was beginning to believe that I may have hit the equipment. I stopped at the exit of the alley; and the Marshall came to the plane followed by the Mechanics. The Marshaller confirmed to me that I had hit the equipment; after which I assumed I would need to stop and be inspected. The Mechanics assessed the damage and gave me hand signals to let me know I was safe to continue with the flight. I knew that if I were to park the plane and inspect the damage myself; I would most likely agree with; and accept the word of the Mechanics that the aircraft was airworthy. As such; I proceeded to de-ice; and had an uneventful flight in VMC.A few suggestions here; first one for myself. Aircraft X was my second plane of the morning; Aircraft Y had a generator fail during my taxi out; and I had to return to Company A and swap planes. I certainly felt pressure to complete the mission as soon as possible; as the route was already 2 hours late by this point. The most prudent thing for me to have done would have been to park; shut down; and inspect the wing myself. I don't know if me doing so would have had resulted in changing aircraft again; but after seeing the damage after landing in ZZZ1; I believe I most likely would have continued in Aircraft X if the Mechanics believed it to be safe. I certainly don't want to lay blame on anyone other than myself; I was the PIC (Pilot in Command) and all events that transpired were my responsibility. That being said; the wing walker on the left had the sole responsibility of helping me avoid obstacles on that wingtip. That wing walker took no action to prevent the impact. Additionally; they did not have me stop and have the aircraft inspected immediately after the impact. Had I not stopped at the end of the alley; I wouldn't have known about the impact until arriving in ZZZ1. I know from conversations with other pilots and our employees that Company A marshallers and wing walkers are not always as proficient as they should be; and may not fully understand what to do in this type of situation. I strongly suggest action be taken to remedy this. Also; I understand that it isn't necessarily feasible to plow that entire alley; but the red lines and the centerline should most certainly be clear before being utilized by aircraft.