My carrots dug in the fall last all winter.
I wash them good. Cut the top green off down to the end (get all the green). Dry them completely. Bag them in a high density bag like the bags you get in a store, and I put them in the fridge.

They have to be dry or they start to grow or rot. If you notice moisture take them out and air dry them again.

This for me, works better than sand because they seem to last longer and stay sweet, juicy and crisp for months.

Peace.
Rustic