April 25–28 Epic tornado outbreak in the USA

A violent tornado outbreak from April 25 – 28, 2011, affected the Southern Midwestern, and Eastern United States, leaving catastrophic destruction behind. At this time there are more than 350 casualties confirmed but the number is still rising.

It was really an amazing setup, just by looking at the numbers. These were the conditions in Alabama:
CAPE : 1000-2000 J/kg
0-6km shear: 70 kts
SREH3: 1100 m2/s2 (!!!)
Significant tornado parameter : 13.0
Supercell composite parameter : >40

These numbers are mind-blowing and we probably won't see this kind of setup for quite some time.

Some interesting images from the supercell that dropped the tornado that hit Tuscaloosa and Birmingham:

Tornado track in Tuscaloosa.

Tornado tracks clearly visible from space. Look how huge the track is! Credit: NASA

Most violent supercell of this tornado outbreak in Alabama.

Crazy hook echo with debris ball.