In all, the entire tornado outbreak killed at least 400 people and injured 213.

One prime example was the April 25-28, 2011 tornado outbreak.

Major tornado outbreaks have occurred in every month of the year.

During the afternoon of April 14, a possible significant tornado outbreak started setting up.

It is the largest and most intense tornado outbreak ever to hit this region.

Conditions were favorable for an extremely strong tornado outbreak on both days.

The college was damaged heavily in a tornado outbreak on April 7, 2006.

It was the biggest tornado outbreak in the planet's recorded history.

Heavy rain impacted areas to the North of the tornado outbreak.

There have been many tornado outbreaks in Oklahoma, some more notable than others.