Task: Question Answering
Input (English): Background Paragraph: Blue ice occurs when snow falls on a glacier, is compressed, and becomes part of the glacier. Air bubbles are squeezed out and ice crystals enlarge, making the ice appear blue.

Small amounts of regular ice appear to be white because of air bubbles inside them and also because small quantities of water appear to be colourless. In glaciers, the pressure causes the air bubbles to be squeezed out, increasing the density of the created ice. Large quantities of water appear to be blue, as it absorbs other colours more efficiently than blue. A large piece of compressed ice, or a glacier, similarly appears blue. 
Story: Grace has been hearing stories about some fantastic sites in the Arctic. She heard about a phenomenon called blue ice and has been wanting to see it. She has some options to go on her vacation, and has been researching them. Her two options she has narrowed down is a small lake called Tiller Lake, and a glacier called Munson Glacier. 
Question: Where should Grace avoid going if her goal is to have the best chance at seeing blue ice?
Output (English): Tiller Lake.