Looks like the top clump with five tubers was planted this spring with a single mother tuber, while the other two massive clumps were not divided the previous year.

I would have recommended you NOT wash them, and store wrapped in newspaper in a loose plastic shopping bag until spring, when you could divide out small chunks or tubers with sprouts.

Since you obviously already washed them, I'd recommend you dividing the monster clumps 2-3 times to make sure mold doesn't destroy the whole clump. A good way of doing that is to pull apart the stalks, not worrying unduly about losing the odd tuber here and there. The idea is to make sure the inside can thoroughly dry and cure before packing away.

Hope this helps!

Doing it now might be... frustrating... to say the least. Many old-timers that are given undivided clumps like that end up thanking the person for their gift, then run the clumps to the compost pile as quick as they can after the person is gone. It is simply not worth the time and effort for them.

I tried to do this to another clump today, and the dratted stems popped right out of the clump, leaving the same tight ball of intertwined tubers. I grabbed half with each hand, and sharply twisted the parts away from each other, with the same effect as the image here.

Granted, this is with one year clumps. I have not had the dubious pleasure of trying to divide a five year clump!