Randomness and starting base

Okay, first off, NS was completely different. Besides, he's not a favorite author of mine anymore. He's good, but not my style. I like Dick Francis and Christopher Paolini, as well as some others, of course.

Seminary news.
Yesterday was five people. Today was... 6?

Okay, to get to the point, I am now going to do an improv writing base (prologue) of a story which I will later expand on.

Running. There was a dark cloud over the city, creeping further and further over the streets. People were yelling, yet all sound seemed to cease within the unnatural dark that advanced. The house. They would be safe there. Clarissa grabbed her brother's hand and ran out of the park, sprinting down the asphalt road for several blocks before turning onto a crossing street. There it was. Alan was shaking now. He kept looking back at the strange mist. "What is it?" His voice was weak. Shaking. "I don't know. Just keep going, we're almost there." The two siblings ran into the house, Clarissa closing and bolting the door. They could still hear the screams outside. Alan went to a corner and curled into a ball, his eyes wide as he looked around the warmly lit entry hall. "I wish mom and dad were here." The whisper carried across the room to where Clarissa was trying to dial 9-1-1. "It isn't working..." Just then the darkness reached them and the lights went out. Everything was gone. Sound. Light. The screams that would have filled the room were stopped by the strange fog. The phone fell to the ground. Shadows of figures were drifting around them. Clarissa stared at them in horror, one turning towards her. Pale green eyes flashed open... And then it was over.
Clarissa got up and looked at the gray alarm clock resting on the dresser beside her bed. 1:16 in the morning. She went into the bathroom and looked at her reflection in the mirror. She was pale, her dark brown hair was disheveled. She stood there a moment, letting her breathing slow before walking back to her room. On her way there, she noticed something lying on the ground by the living room. The phone...

Wow... I can see why books aren't written off of the top of peoples' heads... Anyway, I guess it's something to start with. See ya!