Raising snow

I know it must be quite simple to convert falling snows in raising snows using these codes

onClipEvent (load) {
//variables
width = 300;
height = 200;
//random x,y, and alpha 
this._xscale = this._yscale=50+Math.random()*100;
this._alpha = 20+Math.random()*50;
//random x and y for flakes
this._x = -width+Math.random()*(3*width);
this._y = -10+Math.random()*height;
//speed and trigonometric value
i = 1+Math.random()*2;
k = -Math.PI+Math.random()*Math.PI;
rad = 0;
}
onClipEvent (enterFrame) {
// horizontal movement
rad += (k/180)*Math.PI;
xmovement = _root._xmouse;
this._x -= Math.cos(rad)+(xmovement-(width/2))/50;
// vertical movement
this._y += i;
// remove clips when they misbehave (overstep boundaries)
if (this._x>(width+50)) {
this._x = -45;
this._y = Math.random()*height*2;
}
if (this._x<-50) {
this._x = width+45;
this._y = Math.random()*height*2;
}
if (this._y>=height) {
this._y = -50;
this._x = -width+Math.random()*(3*width);
}
}

But i can’t manage to do it right, pls help.