This is the first time I see a frozen lake. By the time I reached the Long Lake(长海）, it was almost 2 pm in the afternoon. Although it was winter, but it was quite "warm" already by then and not as freezing cold as in the early morning. Might be with all the walking (& exercising) contributed to heat generation.. One good thing to travel in winter is I won't sweat ;)
The Frozen Long Lake (长海）is the largest lake in Jiuzhaigou. (altitude 3,100 meters, measuring 4.4 km in length and 88.8 m in depth). During winter, the lake is frozen over with a depth of 60 centimeters and covered with ice.
The lake has no surface outlet. Water leaves the lake through a subsurface karst system, replenishing the lakes in Rize and Shuzeng valley. Local folklore and legends features monsters in various lakes in Jiuzhaigou, notably Long Lake(长海）, Arrow Bamboo Lake (箭竹海) and Nuorilang Lakes (诺日朗群海).