Tropical glaciers can be found (or could once have been found) not far from the equator in Papua: Ngga Pulu, just under 16,000 feet high, sports an ice cap.
As for the steepest elevation, 30,000 feet may not be completely realistic but you might take inspiration from Mt Thor, Canada, the steepest vertical drop on Earth at 4,101 feet:
The cliff was created by glacial erosion scouring a steep wall as it formed the adjacent valley. The cliff's angled at 105° or more vertical than vertical!