When something goes completely missing, it is often a dry head rather than a clog. Clogs show up as nozzle lines in the same position - yet even those can sometimes be wiper marks. I do not know where you are in the universe, but here in Vermont we need to put about 25 liters of water into our air a day in the studio to just keep it at 35% rH. Epson states that 35% is the minimum humidity level for their print heads. VM, M and Yellow are the heaviest of our inks.
Unless it is some other maintenance issue - you may benefit by buying an inexpensive digital hygrometer and keeping the humidity between 35% and 65%. If we stop our humidifier the heat in our studio will dry the space to single digits and our printers behave the same way. If we keep above 35% rH then the printers are happy. This has always been our experience with both the Epson inks and the ConeColor inks.
We're really vigilant about rH because it also affects color management. We try to keep it uniform between 35 - 40 rH.
Let me know what you find out about your ambient.