The work of three rescue teams tasked with saving truck drivers trapped in freezing conditions along Sierra Nevada's perilous Donner Pass.
massive downfall of snow causes accidents on the Donner Pass, leaving the rescue team attempting to keep the traffic moving.
Sam battles to tow a vehicle to safety in the worst snowstorm of the season. Meanwhile, trapped in a freezing traffic jam, Eddie's wife goes into labour.
Tower Brandon narrowly escapes death on the highway. Meanwhile, Becky is forced to relive tragic events when she is called to a deadly accident.
The rescue team races to a frozen lake to retrieve a sport utility vehicle that has fallen through the ice, trapping its driver inside.
The tow teams face the task of clearing the entire highway of trucks after an emergency warning was issued when a blizzard hit the pass.
Storms turn the Donner Pass into a deadly sheet of ice, causing problems for both drivers and rescue teams.
As the season comes to a close, Justin and Sam both have near misses, and a driver vows to leave the mountain for good.