Selco over at SHTF School gives us 5 symptoms to look for that indicate that a SHTF scenario has started.
Here's a brief rundown on the topics he discusses:
Best information is a key for survival.
Symptom 1: More violence in your area
Symptom 2: Group behavior changes, survival brings people closer and makes others less human
Symptom 3: Dead streets
Symptom 4: New leaders emerge
Symptom 5: Nobody to trust anymore
Go and read his in depth analysis. He knows. He's experienced it.