A vocabulary of landscape — a landscape of words 975 entries

verglas

vehr-GLAH
A thin, transparent glaze of ice over rock. Extremely hazardous — crampons can’t penetrate it and rock shoes can’t grip it. The rock looks bare until you touch it and your hand slides.
Etymology
 French — verre (glass) + glas (ice), literally “glass ice.” The word entered mountaineering English through Alpine climbing.