Blame the empty shelves on hoarders who stockpiled the plush paper goods. During a two-day period in March, online and in-store sales shot up a whopping 845% as states announced stay-at-home orders, according to NCSolutions, a data firm.

Since toilet paper is bulky and not profitable, retailers don’t typically keep a lot of inventory on hand. That makes it hard for them to keep up when demand suddenly surges.

Americans are also using more toilet paper at home now, instead of at places like offices and schools. Yet companies can’t just redirect supplies of the big institutional rolls, which are manufactured and packaged differently.

Demand has since softened and retailers are limiting the number of rolls customers can buy at once, so it should be easier to find rolls on shelves these days.