Confusingly, UKTV channel Dave refer to the extended XL version of this episode "Ice" as Series 09 Episode 15. And perhaps even more confusingly, the BBC channel BBC Brit (which only airs the 30 minutes version) lists this episode as the 14th of Series 10.
This edition isn't the traditional QI Christmas themed edition you may expect. This one focuses on snow and ice in a more general theme.