A wrong step could be fatal. Downed power lines may still be live. If you touch one, you won't be. Gas lines may be leaking. A spark from a cigarette or an electrical switch could trigger an explosion.
Broken glass can shred feet, especially children's.
Nails and other sharp debris are everywhere. Snakes and other dangerous critters may be lurking. Your water is probably tainted. Looters may be down the street. On top of all that, you and your neighbors have just gone through the scare of your lives.