Yes. Mulch, and cover. Try to keep no colder than 50 deg.

I would cover the artichokes but the brassicas should be fine. Snow is a good insulator anyway,

Where the heck are you?! It's still summer in the Northern Hemisphere.

OP is probably in Montana or Wyoming. Alberta (Canada) got dumped with up to a foot of snow in some places, with lows down to the mid-teens in a few areas.

The weather has been crazy for some of us! Northern WA/ID hit hard frosts. We just got low to mid 30s. Going to be in the 80s/50s in a few days.