"Diving in freezing water -- water temperatures were 28.8 degrees Fahrenheit -- can be tricky. But its not as harsh on the gear as you might think. There were days where we had topside conditions of negative 40 degrees Fahrenheit and the saliva in my mask immediately turned to ice (you spit in the mask before diving to prevent fogging during the dive). My drysuit froze up so I could barely move. But since water can only get so cold before it freezes, the underwater environment is relatively warm and at least predictable". --Norbert Wu, cinematographer