Yes, they will keep shrivelling and having them on cement is particularly dehydrating according to Plantlady's previous posts. Get them cut up and wrapped soon and you should be okay.

You didn't dig too soon. Sounds just right.

Flowergirl, I'm a bit confused about the mention of "I planned to cut them up and wrap them in saran wrap".
In what way was that meant to be taken?

There is a method that is explained in the "Dahlia Society" website which entails removing all the tubers from the clump and wrapping them in saran wrap AFTER allowing them to dry out for a day or so.
Moisture should not be cocooned with the tuber as it can set up mildew over the span of storagetime.

I have yet to try this method....I shrink from removing the tubers from the clump considering the loss of 'eyes' will prevent their re-appearance next spring.
The clump that is uplifted I treat gingerly so as to protect all the tubers from falling or being knocked off.
I then allow a couple days of storage before they are given a peat moss cover and stored in my coldcellar where they remain cool, dark, and dry.

Shrivelling is part of the tuber's drying out and unless it shows signs of softeness, or mold, I trust it is in good shape for storage.

The time of digging is as you point out....letting the plant be touched by a killing frost which blackens the foliage. Then, all that is removed and the stem is cut back, except 6", serving as a good handle to lift them out when unearthed.

You use a refrigerator to store the tubers.....so I assume then you remove all from the clump, saran wrap them, then store them.

Question: have you had passed success with them doing this way?

The tubers that were planted last spring grew in numbers over the summer. What clump went into the ground at that time, is not the same size that came out. Do you not have large volume of tubers doing it this way---the refrigerator.

Yes, I have used the saran wrap method before with good results. There is no way to wrap them up without cutting them up. I split the stems so as to have eyes for the tubers. Of course they multiply, I save the best looking ones and trade with my friend. This year I only had 13 to dig, so there won't be an overabundance of tubers to begin with. I am not blessed with a cold cellar, and it freezes in my garage. I was just amazed that they started to shrivel up so soon.Oh yes, I dust them with sulpher before I wrap them. The 13 I dug are all new ones. All the older ones I leave in the ground, cover the stems with heavy duty foil, and then mulch with grass clippings.I seldom loose any leaving them in the ground. The new ones I dig so I can trade. Thanks Poochella.