Absolutist thinking is a vicious falsehood, creates only confusion.
Glaciers melting. Ok, that works. Those who live in the glacial region of our planet once engaged in this process. They would go to the glacier and focus all their attention on the glacier. They would likely have to go alone, but would have someone ready to get them later that day and bring them back to the tribal camp. They might lay on the glacier, or stare to the point of almost blinding themselves in the reflected light of the water coming off the glacier. All the while having their ears filled with the sound of the wind and the sounds of the natural life around them. They might have had an attendant present at the very site, but they would be under directions to remain still until the appointed time. They would give themselves over to all the activity of the melting glacier and the world around it, feeling emotions as if their own body was the melting glacier itself. They might begin to have hallucinations that take the form of ancestors they heard about in stories or even more recently departed loved ones who they once spoke to regarding the seasons of their native land, and the voice of the ancestor would not be the voice of a human being but say the scream of the seagull or the barking of a sea lion. As they hear the sound of a walrus splashing back into the ocean, they might become this walrus and experience what is happening in its domain under the ice.
When they come back they would be filled with the emotion of everything they joined, and they might even turn on the person set to get them or watch over them. The oracle or shamans guardian often had to be physically strong and capable of defending themselves.
The ancestors would be part of that memory? They would, yes. When the shaman calmed back down and perhaps partook of a meal, they could work out their experience in their mind and perhaps advise the tribe on what would be necessary to continue to survive as they had become accustomed. But just as often, the shaman might give voice to a threatening warning as if they were not even a member of the tribe, angrily berating the people for some form of neglect that lead to the damage currently expressing itself.
The biblical prophets were often seen as raving lunatics, and they were not members of the priesthood. They often didn’t even have their sanction.
What kind of neglect would cause such damage? Fires, too much ice cutting in one place, too much traffic in that place.
So being careless with the gift of fire? Yes, but for the time being the shaman really is out of his or her mind. They used to believe that shamans were just tribally tolerated psychotics. But they found evidence that they weren’t tolerated. They were respected, even to the point of reverence. Now why would a culture that has to give most of its time and energy to practical survival matters do something like that?
It must have worked. To the point of a war chief being ignored if the shaman spoke against taking hostile action at that time or against the intended people.
Because they believed in the ability of the shaman to commune with nature and ancestors and know the way of things. Yes. They had to go out of their mind in order to go into the realm of power.
Your thoughts are welcome. Be well friends.