Disruptions included banks, airline networks, emergency call centers, online retailers and numerous corporate networks. The outage is estimated to have caused at least $5.4 billion in profit losses and it only lasted about a day.

The alleged cause of the breakdown was Crowdstrike, a cyber-security company that uses large scale data updates to Microsoft Windows networks to counter cyber threats. Instead, the company uploaded bugged code and caused a cascading outage. Mac and Linux machines were not affected.

The scale of the shutdown was immense – Over 25% of Fortune 500 companies were frozen. Travel essentially stopped. Business transactions for many companies ceased. Some banks including Bank of America, Capital One, Chase, TD Bank and Wells Fargo could not function and customers could not access their accounts.

The event reminded me of the panic surrounding the Y2K scare 25 years ago. Of course, that was all nonsense; US systems were definitely not digitized to an extent great enough to cause a disaster should there be an internet crash or a software crash. But today things are very different. Nearly every sector of the American (and European) economy and many utilities are directly dependent on a functioning internet.

The fear that prevailed during Y2K was unrealistic in 1999. Now, it makes perfect sense.

I often hear preppers talk about the impending danger of an EMP leading to a grid down scenario. However, this kind of attack is highly overblown. Even major solar storms have not caused the kind of electrical breakdown that theorists suggest might happen. Instead, I would recommend worrying a lot more about cyber threats. I believe these events will become far more common in the next few years for a number of reasons.