It was 75 feet high and filled with garbage, which can act as an insulator. Also, as more of it melts, the garbage stays so more of the pile is insulating junk.
It is going to be there a while.
How many dead winos do you think we’d find if we tore down that pile?
Ice houses of the old days, harvest ice in the winter, pack it in sawdust, and you have ice all year.