The Glyderau (a Welsh plural form, also known in English as the Glyders) are a mountain group in Snowdonia, North Wales. The name derives from the highest peaks in the range, Glyder Fawr and Glyder Fach. According to Sir Ifor Williams, the word "Glyder" derives from the Welsh word "Cludair", meaning a heap of stones.
Intro to night and poor visibility navigation for 2 assistant instructors. 
