So I'm writing a book and I have a prologue that takes place a week prior to the actual beginning of the story. I sort of want to expand the prologue a bit but I'm not sure if I need to or how. Could I have some help? Here it is:

Prologue

It was a strange day in terms of weather: Though it was sunny, the light was dulled by thin wisps of cloud, almost white and yet just gray enough to threaten rain. In the air hung moisture that felt like a sauna and in town, windows were fogged over as if children had blown their breaths onto the glass. The muted sun seemed to mute the temperature as well. That might have been why the swamp felt cool that day. Animals that normally hid from the smothering heat crept about freely in the forgiving air. Birds rustled leaves as they flittered about in pairs or flocks. Every so often one of the thousands of insects hovering in the air was snapped up by a frog or gulped down by a fish, if it decided to sit on the water for long enough. Nutria the size of small purse dogs waded in cool ponds covered with lily pads and algae. In the largest pond, an alligator was lurking, not noticing as a poisonous snake slithered past in the water. Wind gently drifted through the trees, barely moving even a blade of grass. Other than these natural disturbances, the swamp was calm and quiet; as one may say in a movie, too quiet. A quiet like that in the swamp could not last long. Something would have to come along and ruin it. That something was unnoticeable at first: a slight ripple in the middle of the largest swamp pool. Then, a splash of water as fish suddenly flashed away, followed by the alligator. The pool began to bubble and a strange glow illuminated the disturbance. Birds and reptiles alike began fleeing. A heron that had just caught lunch dropped her kill and took off in fear, joining the dozens of other birds in the air. Water swirled in the pond, churning the surface into a glowing froth. There was a deafening roar, like the sound of breaking surf. Then, just as suddenly as it started, it ended. The water calmed and the swamp grew quiet once more. The animals began creeping back and soon life continued on as normal, the event forgotten. In the middle of the pool, a small shard of what appeared to be glass floated to the surface.