29 April 2011
This was posted on YouTube today. This is the likely EF-5 tornado that destroyed part of Tuscaloosa, Al. on Wednesday afternoon.
This is what the radar looked like at that moment.
The blob south of the hook echo is called a debris ball, and you see this only in very large tornadoes. It’s caused by the radar beam reflecting off of debris in the air around a tornado. weather radar is designed to see objects the size of rain drops, so there must have been an incredible amount of debris in the air to show up like this. It’s the biggest debris ball on radar I have seen in 32 years as a forecaster.