If you look at the Ahwahnee Meadow cam you can see that there is no snow so I am sure that the valley roads are clear of snow. However when we were there a few weeks ago, there are places on both Northside and Southside Drives that had water running across them and had some potholes like you always see after a winter when Yosemite has gotten this much rain and snow. As for chains, it is mandatory to carry them through the end of March but I doubt if they will be checking if you have them if there are no storms coming in but it is up to you if you want to go without chains. It was cold and snowing when we were there and there was snow on the 41 in places but now it is hot so the snow most likely has melted.