The home terror alert system that a friend of mine and his children use to warn each other of their mother’s mood. It is a simple system based on a series of flags.

One screaming head on the flag = normal threat level, be ready to duck.
Two screaming heads on the flag = slightly elevated threat level, wear your Kevlar.
Three screaming heads on the flag = elevated threat level consider sleeping in the dog house.
Four screaming heads on the flag = serious threat level take over the dog house for a few days.
Five screaming heads on the flag = mom found the combination and got the gun safe open.