while (doStorm) {
    int radius = plugin.config.getInt("storm.radius", 1);
    for (Player p : Bukkit.getServer().getOnlinePlayers()) {
         Block b = p.getLocation().getBlock().getRelative(random.nextInt(radius)- radius / 2, 0, random.nextInt(radius)- radius / 2);
        Location loc = b.getLocation();
        p.getWorld().strikeLightning(loc);
    }
}