There is a post on tumblr by Going-banannas, with a photo of Kara where she appears unconscious and falling from a building. Someone has posted that it is from the Flash crossover and it was when Silver Banshee struck Kara with her scream. I wrote this before I knew it was Silver Banshee, so I'm sticking with Livewire instead.
More than Average
There was no scream, no cry for help as Kara disappeared over the balcony railing. Only a blinding flash of light as Leslie unleashed her godforsaken powers.
A moment before Cat had seen her hands raise, seen the power flowing to her fingertips. It would be over in an instant. Her only thought had been for Carter. She hadn't time to finish a silent apologize for leaving him, when the blinding white light streaked toward her chest.
She could feel the energy crackling through the air as the bolt drew closer. Something solid crashed into her side, sending her sailing to the ground at the corner of the balcony.
The energy bolt struck Kara's chest dead center, for a moment her whole body glowed as the energy enveloped her. Then she was launched back and up, over the railing. Her heels clipped the edge, flipping her backward out of sight.
The air stank of burnt ozone. As the final pulse faded, silence filled the air.
Siobhan rushed to the railing, rising to her toes to look down. "Damn it, I told you I wanted to kill that blond witch."
Leslie shrugged. "Better luck next time." She turned toward Cat. "Let's finish this."
Siobhan grabbed her arm. "No, we need her, remember?"
"Fine." Leslie snapped.
Screams and car horns began to drift up from the street. Cat didn't have to look to know what the scene below would be like. Years of suicide stories had shown her in great detail the damage done to human bodies from high falls.
Her stomach twitched at the thought of Kara suffering the same fate as those hapless souls. Somewhere in the deep shadows of her mind she hoped Leslie's energy blot had killed her. At least it would have been a quick death. Pushing away the thoughts she shifted, her hand blushed against something on the ground.
She picked up the glasses, turning them in her hand. Average glasses for an average girl, with less than average vision, she bit her lip at the memory as tears threatened to cloud her vision. Anger and a sense of loss rushed over her in an overwhelming wave. With a deep breath she locked down the flow and steeled herself. She folded the glasses closed and slipped them into her pocket. There would be time to grieve later, right now she needed the weapon she wielded best, power.
She looked up at the two women standing before her. Nether were worthy of the powers they possessed. And she swore a silent oath that they would pay dearly for robbing the world of one of the few descent people living on this rock.
With that thought she stood, brushed a hand over her slacks and fixed them with a glare. "So you two idiots have plan? I find that hard to believe. Let me guess, you are trying to lure out Supergirl. Good, I look forward to seeing her kick your worthless asses up and down the street."