permafrozen

From perma- +‎ frozen.

permafrozen (not comparable)

1. permanently frozen
   • 2006, Terri Farley, Phantom Stallion #21, page 210:

     Piece of cake? her mind screeched. Piece of ten-million-year-old permafrozen glacier, maybe.

   • 2001, Graham Taylor, R.A. Eggleton, Regolith Geology and Geomorphology, page 239:

     Pingos form by the penetration of unfrozen but saturated sands to the surface through a layer of permafrozen ground.

   • 1980, Robert Auty, Companion to Russian Studies: An Introduction to Russian History, page 11:

     With the very long winter, permafrozen soil, and low evaporation, the soil is waterlogged.

• permafrost