[FL410]

I am confused by the slide, which mentions in the first bullet point that this is the first "G4" since 2005, but in the last bullet point says there was one in March.

[Shank]

It’s the first G4 watch, but not the first G4 event. In other words, the prior G4 event was not predicted. It can happen that an event is more significant when it arrives than what was predicted, which is what happened here.

[anileated]

A G4 storm was forecast yesterday, but guess what—a G5 was observed: https://www.spaceweather.gov/news/g5-conditions-observed. As with G4 before, not predicted.

[webdoodle]

It also resulted in Aurora visible in Mexico.

[uticus]

it's a typo, Mar 2024 was a G3, not G4. ref https://news.ycombinator.com/item?id=39796973 and link in comments there.

[edit] i stand corrected, there was a G4 in march. sibling comment is correct. ref https://www.swpc.noaa.gov/news/severe-g4-geomagnetic-storms-...