Can Frozen Hydrogen Snowballs Account for Galactic Dark Matter?

It is believed that perhaps 80% of the total mass in most galaxies is distributed in a halo that is larger than the galaxy itself, but is not associated with stars or other known physical objects. Most candidates for dark matter are novel fundamental particles, rather than ordinary atoms. It is suggested here that a more prosaic explanation should be reconsidered: that dark matter in these very cold extragalactic halos consists mostly of frozen hydrogen and trapped helium, in the form of comet-like giant snowballs. If their temperature is close to that of the cosmic black-body radiation (2.7 K), these hydrogen snowballs should be stable for long periods of time, and may be replenished by collisions. Similar suggestions were made decades ago [1], but not serious considered by the astrophysics community. Possible methods to detect these objects indirectly are discussed.
[1] R.S. White, “Can Baryonic Dark Matter be Solid Hydrogen?”, Astrophysics and Space Science, 240, 75 (1996).