The expectations though, are not based on experiences by average citizens. Experts do know the damage that can be caused by an EMP resulting from a nuclear detonation however, because nuclear devices were tested decades ago.
At the time the nuclear devices were tested and the resulting damage that the EMP created was noted, the electrical grid was not as large, and a number of American families were not yet dependent upon the grid and there were not that many devices, which would have been affected by an EMP. So the experts were not that concerned.
Whether the damage will be as extensive as some experts claim today is yet to be determined. As with any crisis there are varying degrees, but an EMP attack, regardless of severity, will have an impact on everyone.
One problem is that it may take days for information to filter down to the citizen level that it was an EMP attack. In the meantime most people would naturally assume it was a brief power outage. This means that not that many people would be contemplating evacuation in the first 24 to 48 hours.
Those that live in a heavily populated metropolitan area will, in all likelihood, suffer the most from an attack. People living in apartment buildings, for example, may have to leave, because it will become too dangerous to live in a high rise apartment building without electricity.
Even if the building had backup generators they would not last long. In some cases, apartment buildings could become death traps. You do not want to be living on the 10th floor without elevators, smoke alarms, and sprinkler systems or without heat or air conditioning.
In some extreme cases, you could take over a bottom floor apartment if the other occupants evacuated. Being at ground level provides greater options, mainly you can extract yourself more easily if the building is torched or overrun by looters or gangs.
Those living in the city in single family homes would have decisions to make. You would not be able to leave by vehicle even if you had one that operated. The highways, side streets, and bridges would be gridlocked, and any vehicle that operates would be a prime target, so it may be commandeered by the authorities or you could be carjacked. You would be left to get around on foot.
If the EMP is localized other parts of the country would become temporary refuge. However, the fact there was one attack means there would be a high probability of other attacks, so there may be rolling blackouts if you will.
You might assume that the government would counter to prevent another attack, but you could not count on retaliatory action to be successful. This means that if you did bug-out to another area, you may encounter the same problem, but now you have left your home, and getting back home may prove to be an even bigger challenge.
Martial Law may be enacted and this could mean the military could provide generators for temporary shelters. It would take days or even weeks for everything to be up and running however. In the meantime you would have to be able to sustain yourself.
Looting and street violence is a given, and you would have to deal with it. However, in the case of an attack against the country all of the people would have a common enemy, one that attacked the nation as a whole.
The type of civil unrest may be different from what we have seen in the past when riots focused on a particular event that occurred locally. This is all conjecture of course, but certain events in the past have proven that the nation tends to come together when people feel the entire country has been attacked.
Again it all depends on where you live. Some people will not care, and will of course take advantage of any situation. However, more citizens than not will likely rally together, and the anarchists, antagonist, and other trouble makers may be dealt with quickly by other citizens.
You would have to bug-out before the riots began if you expected to be able to get clear of the city. You would essentially have to bug-out minutes after the city went dark. The minute the lights went out you would have to assume the worst and be ready to leave.
Most people could not, or would not make the decision to leave minutes after the power went out. You would naturally want more information, but it would be difficult to get any information in the hours after. You would have to make some assumptions.
What would cause violence and riots more than anything else would be the lack of necessities. Water, food, medicines, and in some cases the lack of safe shelters. You may not have to worry about looters because so-called friends and neighbors may turn on you for what little you may have.
The authorities would be aware of this fact, but whether they can do anything about it is another story. Attempts would be made, and the focus would be on the areas suffering the most. Your area may be a low priority. Whether you survive or not depends on how well prepared you are.
Some people have actually stated, whether jokingly or not, that they welcome a power grid failure for various reasons. You have to assume most are not serious, but some would be. The ones that secretly wish for it to happen will be in for a rude awakening, because they have over anticipated their own abilities. They will be affected, and not in a positive way, whether they believe it or not.
Those waiting for life saving surgeries or other life saving medical care will die. Those that cannot live without dialysis will die. Babies born prematurely will die, without electricity. Untold numbers of others will die because they will attempt to cobble together generators and from tinkering with equipment and tools with which they have no experience.
Food poisoning cases will rise and so will deaths from drinking bad water or from lack of water, lack of heat or from lack of air conditioning. Then there are those that will decide now is the time to extract revenge against a co-worker, spouse/partner or even friends, so the murder rate will spike.
An EMP will likely happen at some point. It may even be an accident that causes an EMP that would result in a grid failure just like a nuclear detonation could be an accident. At some point the reason would become irrelevant to most of us. We will be trying to survive the fallout, trying to survive without a food and water supply chain. Without medical care and trying to survive without help from the local authorities, that do more for our very existence than we may realize until we have to survive without it.