Hi skipvia. Yes, I'd pounced on it immediately as a monovocalic, but then couldn't confirm it with a Google Book search.
I found "Névé penetente A tower of ice that resembles a person praying" (Frederic Hartemann and Robert Hauptman, 2005, The Mountain Encyclopedia, 2005, p. 156) and "From there they decided against crossing to the left glacier that descends the face because of its 'forest' of penetentes... (American Alpine Journal, 1929, p. 406). But those two seemed misspelled against more than 500 instances of penitente: "neve penitente", 19; "neve penitentes", 6; "nieve penitente", 491; and "nieve penitentes", 52.
Sharp ice peaks formed when sunlight reflects off of small depressions in the snow cover, melting the snow unevenly and forming tall peaks. Typically found when traveling on a glacier. When these refreeze at night, they can become quite hard and sharp, making travel difficult. Climbers usually call them neve penetentes. Nice image here.