Yes, but Palisades is latitude 39.2 and Portillo is 32.8, same as San Diego. I think that area of the Andes is absolutely world class for corn formation (high altitude, clear weather night and day), but the meltdown of snow at that latitude can be quite strong. The latitude difference would translate to a northern destination at similar altitude about 3 weeks later. So at this point I think it's somewhat important that the snowpack gets refreshed in August before we can count on full coverage in mid-September. In 2007 there were areas (widespread in La Parva) that had lost coverage during the prior warm and dry 3 weeks.The more relevant question: would you ski Lake Tahoe in March (September) after potentially no snow for 2-4 weeks, but a 100-200-inch base and temps (Low 20s, Highs 50s) at an area like Sugar Bowl or Alpine Meadows? With some of the best corn snow? Some south-facing chutes might preserve surface conditions well, but most terrain will require following the sun.
I have had friends visit, and we ski Tahoe in March after weeks without snow. You can have a great time and follow the sun.