News4's "Debris Detector" was key in picking out last night's tornadoes. While only one tornado has been officially confirmed by the National Weather Service so far with ground truth reports, several tornadoes were actually "radar confirmed" because of what we saw on Debris Detector last night.
So what IS Debris Detector anyway? It's a way the radar can show when there's more than just rain or hail in the air -- when trees, 2"x4"s, or even chunks of homes are also filling the sky. The radar does this through analyzing the shapes of the items it detects.
Last night, the 4WARN Weather Team located several areas of rotation. Take for example the spin near Christiana around 12:30am. Red colors on "Rotation Detector" show wind blowing away from the radar. Green colors show wind blowing toward the radar. Where those different colors are close to one another, there's rotation or spin.
Here's a more zoomed in view of Christiana just after midnight.
While tracking this storm, we knew this rotation was in fact in contact with the ground (i.e. a tornado) because of Debris Detector! Notice lining up exactly where there rotation was, there was a distinct pocket of yellow and blue on Debris Detector. Those colors mean particles of very varied size and shape were filling the sky (e.g. rain mixed with tornado debris). Where there was red, just rain was falling.
Here's another great example, near Auburntown. Notice the rotation.
Here's they way the storm looked on Debris Detector over that very same spot.
In all likelihood, this Auburntown storm will also be classified as tornadic over the next day or two. Many other storms will also follow suit.