Created in a Tub at high altitude, about 180' or higher. Available at night time (6pm-6am). Add 20 water to tub, wait for it to evaporate.
Ice Block in inventory melts at 10am give or take a couple of minutes. 8 Sturdy Tubs in cp and ice blocks had not melted by 12:00pm.
Spouse Warping with Ice Blocks in your inventory will melt them and give you a message in main 'You feel wet.'