The grid frequency across continental Europe plunged to 49.85 hertz — just a hair above the red-line collapse threshold.

The normal operating frequency for Europe’s power grid is 50.00 Hz, kept with an extremely tight margin of ±0.1 Hz. Anything outside ±0.2 Hz triggers major emergency actions.

If the frequency had fallen just another 0.3 Hz — below 49.5 Hz — Europe could have suffered a system-wide cascading blackout.

At that threshold, automatic protective relays disconnect major power plants, and collapse accelerates.

And it's disturbingly easy to imagine multiple scenarios where that could have occurred...

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