South Dakota spins up the twister of the season.

Tim's team chases in the tornado twilight zone; Sean weathers controversy.

Storm and chasers collide in Minnesota for a final showdown.

The chase teams are on the front lines during an epic tornado outbreak.

The teams follow a storm headed toward downtown St. Louis.

Reed takes his team on a dangerous nighttime chase.

The teams help with the recovery effort in Alabama and Mississippi.

Reed and his team take the day off, but it backfires.

A tornado outbreak threatens to wreak havoc in Reed's backyard.

Sean tries his team's patience, and Tim makes questionable decisions.

The chase teams have one last chance to achieve their goals for the season.

It's a bad-news week as the crew struggles to make up for lost time.

The Pelletiers face another rough week catching up on behind quotas.

The crew struggles to catch up after a hurricane slows down production.

A veteran driver succumbs to treacherous road conditions.

The guys battle snow and subzero temperatures after a Nor'easter hits.