Frigid temperatures wreak havoc on Dawson City, putting the fire department in danger; an avalanche shuts down the Klondike Highway and a tow operator races to find a driver who has plunged off-road and into an icy river.

Multiple 911 calls push Dawson City to the brink as they battle to save a family home and a historic building, while snowstorms pummel Whitehorse, causing chaos and forcing a dangerous backcountry helicopter rescue mission