Last year I stored my carrots in sand and I wasn't happy with the results. A lot of them rotted. Plus you have to wash off all that sand and where are you going to do that in the middle of winter so it doesn't clog your drain? One mistake I may have made is I washed them before I put them in layers in the sand. I read that you aren't suppose to wash them but they were caked in mud. This year I read a comment in a blog by a 71 year old woman who has been gardening her entire life and am going to take her advice.
I washed the carrots and let them dry outside laid out on a ledge. It was cold outside so I put them in the sun. Dry them no more than a couple of hours. I cut off the greens (green tops will cause rot) and the tails. I bagged them in Ziploc bags and left the bag open a crack. I am fortunate to have a root cellar and that is where they are stored. I hope this year works better than last.