Assuming you have brought them inside or otherwise thawed them out -- if they are soft or mushy ... yes, they are well and truly dead. If they are still hard then they may very well be alive. Btw, you may want to experiment next time and leave several in the ground. My folks live in z5 and have never dug up their glads. They have returned year after year for more than decade now. (Ironically, the type marketed as being winter hardy in their zone never did make it past their first winter.) Now my folks do tend to get a lot of snowfall so that might be a factor.

I stopped digging up glads 10 years ago. They survive very well here in CT.

Glads seem to be hardier than traditional wisdom says - they survive for my dad outdoors even after last winter's -15F several times.

However, 22F with no soil around them might be too much.

Agree - my glads are doing well even after last year's terrible winter. Never bothered to dig them up.

It all depends: if corms freeze they are toast. Mulch will help if not enough snow to prevent the ground freezing. After a few years they should be dug and divided to maintain spikes size.