Cessna 402/402C/B379 Businessliner/Utiliner
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Provided Assistance; Flight Crew Took Evasive Action; Flight Crew Returned To Clearance
Weather
While at 8000 feet enroute to ZZZ; we entered an area of IMC. Several minutes after entering the area of IMC roughly 100 miles NE of ZZZ; my first officer and I began to hear and observe rain droplets roughly the size of quarters impacting our aircraft. OAT was -10 C and the SLD's (Super-cooled Large Droplets) froze upon impact. The ice accumulated rapidly; building to approximately 2' in less than 30 seconds. Upon entering the area of freezing precipitation; I disengaged the autopilot and descended to 7000 feet. While doing so; we also communicated with ATC: was cleared down to 7000 feet and made a PIREP. Once at 7000 feet; we were out of the area of icing conditions. I then activated the de-ice boots which cleared the wing of most contaminates. The flight continued without issue until approximately 20 miles outside of ZZZ were we once again encountered icing conditions. The ice accumulating was light to moderate continuous mixed and the de-ice boots were able to adequately keep up. Knowing that the aircraft was contaminated with ice; I chose to keep power up while landing and also keep my landing attitude relatively flat to avoid a main wing stall; though the aircraft did begin to buffet just before touchdown. I would like to add that there were no PIREPS made prior to our departure regarding icing and the region had light to moderate ice forecasted throughout the region at all altitudes we are able to legally operate at.There was patchy areas of precipitation dense clouds all over [the area] that day. Aircraft; including our own aircraft experienced ice intermittently throughout the day; although nothing other than light mixed was reported. It just so happened that we unknowingly entered a cloud that was extremely moisture dense and flew into an area of SLD's. We quickly took evasive action to address the issue and in less than a minute; we exited the icing and continued to ZZZ without further disruption.
Air taxi Captain reported rapid onset of moderate continuous icing while in cruise and on initial approach.