Nightly News | May 20, 2013
>> headquarters in atlanta. chris, if there is any blessing, we did know this severe weather band was coming through. this was a broad daylight occurrence. at least sirens were blaring and at least this didn't hit in the middle of the night .
>> that is one piece of good news, brian . is bad news is if you did not get the warning, the only safe place to be is under ground or completely out of the way. because you see these pictures, you see the destruction. from the air and from the ground, it's almost impossible to even tell what this was. i have been on the ground after tornadoes. it's hard to make sense of what was where and what is now -- it's really mind boggling to see the power of what the storms can do. part of the reason why, you have this rising air. so this debris, the 2 by 4s, pieces of metal, cars are being tossed in the air thousands of feet. you are seeing rescuers doing what they can to sift through the rubble. in many cases the rubble is spread out for miles and miles. again, thousands of feet into the air. brian , right now i want to show you the radar recap. the radar can show you that there was some debris in the air. let's take a look right now at that radar. radar sends out a signal, measures rain drops, green coming back lighter rain. yellow, orange, red is heavier rain. putting it into motion right at the time the storm was moving through moore, this storm at its height, about a mile to a mile and a half wide. so now we are seeing purple in here. that is stuff in the air. that's called a debris ball. when we see this and you see the hook signature where there is likely rotation, we know there is something other than hail, other than rain that is in the air, brian . just looking at the radar without seeing pictures we know we had a dangerous storm on our hands.
>> chris warren from weather channel headquarters. chris, thanks.