When digging out the door and trench of the igloo, if the entire floor is dug out to gain more room, you will run the chance of the entire igloo collapsing due to the underlying snow layers giving way. This has been the cause of deaths when building snow domes/quinzhees as the entire structure shatters from the impact of hitting bottom.
With the ICEBOX® built igloo there is a chance that the igloo will not fracture when hitting bottom but there is no guarantee that it won't.
Here is a picture that a customer sent us where the igloo floor was removed completely and the igloo didn't fall down when the foundation gave way:
The best advice is to only dig a trench and not remove the entire floor.
