I had to one up kirupa’s example 
_root.createEmptyMovieClip("container",1);
var d = 1;
var radius = 5;
wind = 0;
function addCircle(x, y, scale) {
var mc = container.attachMovie("Circle", "circle"+d, d++);
mc._x = x;
mc._y = y;
mc.vx = Math.random()-.5;
mc.vy = Math.random()-.5;
mc.t = 0;
mc._xscale = mc._yscale=scale;
mc.colorobj = new Color(mc.coloroverlay);
return mc;
}
function makeSnowParticle(x, y) {
mc = addCircle(x, y, 3+Math.random()*2);
mc.growthi = -1;
mc.track = -1;
mc.falling = false;
mc.isSeed = false;
mc.setHue(.3);
mc.onEnterFrame = function() {
dx = 250-this._x;
dy = 150-this._y;
this._x += this.vx+wind;
this._y += this.vy;
if (!this.falling) {
this.vx += dx/80000;
this.vy += dy/80000;
} else {
this.vy += .02;
if (this._y>300+this._width/2 && this.parent != null) {
this.removeMovieClip();
}
}
if (!this.isSeed) {
dx = seed._x-this._x;
dy = seed._y-this._y;
d2 = (dx*dx+dy*dy);
if (this.track == -1) {
if (d2<3500) {
this.growthi = -2;
this.colorobj.setRGB(0xFFFFFF);
this.track = seed.growthi;
this.parent = seed;
seed.growthi++;
this.filters = [];
makeSnowParticle(random(500),random(300));
if (seed.growthi>=36) {
seed = null;
setSeed();
}
}
} else {
this._xscale = this._yscale += (10-this._yscale)/15;
this.p = getParticlePosition(this.track, this.parent.t);
dx = (this.parent._x+this.p.x-this._x);
dy = (this.parent._y+this.p.y-this._y);
d2 = (dx*dx+dy*dy);
var fx = .01*dx-.08*this.vx;
var fy = .01*dy-.08*this.vy;
this.vx += fx;
this.vy += fy;
if (seed != this.parent) {
this.parent.falling = true;
this.falling = true;
}
}
} else {
this.t += .01;
}
};
return mc;
}
function getParticlePosition(i, rotation) {
if (i<18 || i>=30) {
var normalizedi = i>=30 ? i-12 : i;
var ri = 1+Math.floor(normalizedi/6);
return {x:ri*radius*Math.cos(rotation+Math.PI/3*normalizedi), y:ri*radius*Math.sin(rotation+Math.PI/3*normalizedi)};
} else {
var normalizedi = i-18;
var t = Math.PI/3*normalizedi;
var s = normalizedi<6 ? 1 : -1;
return {x:3*radius*Math.cos(rotation+t)+s*radius*Math.cos(rotation+t+Math.PI/2), y:3*radius*Math.sin(rotation+t)+s*radius*Math.sin(rotation+t+Math.PI/2)};
}
}
MovieClip.prototype.setHue = function(x, mc) {
//x = 0 - 1
x = Math.max(x*2*Math.PI, 0.01);
r = 128+128*Math.cos(x);
g = 128+128*Math.cos(x+Math.PI*2/3);
b = 128+128*Math.cos(x+Math.PI*4/3);
var hex = r << 16 | g << 8 | b;
this.colorobj.setRGB(hex);
};
function setSeed() {
seed = makeSnowParticle(250, 150);
seed.setHue(.1);
seed.growthi = 0;
seed.isSeed = true;
seed._visible = false;
seed.t = Math.random()*Math.PI*2;
seed._x = 250;
seed._y = 150;
}
for (i=0; i<=180; i++) {
makeSnowParticle(random(500),random(300));
}
setSeed();
var windt = 0;
onEnterFrame = function () {
wind = .2*Math.sin(windt += .05);
};
