Oui c'est vrai, mais le Kp est quand même un assez bon indicateur de ce genre de phénomènes.
j'ai aussi regardé pas mal d'autres mesures sur la période, flux radio à 10.7cm, mesures EUV, etc... tout cela reste dans la gamme des perturbations assez classiques.

The geomagnetic storm was the result of a coronal mass ejection from the Sun by an M1-class solar flare that lasted for about four hours.

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The geomagnetic storm was the result of a coronal mass ejection from the Sun by an M1-class solar flare that lasted for about four hours, pushing materials into the vacuum of space and towards inner planets including Earth. Experts had warned of a moderately-strong G2-class geomagnetic storm as the flares hit Earth's magnetic field.

Powerful eruption from Sun to hit Earth today, Noaa warns of possible geomagnetic storm

The CME was hurled into open space on January 30 by an M1-class solar flare. The flare lasted for about four hours, pushing materials into the vacuum of space.

IndiaToday.in India Today Web Desk
New Delhi February 2, 2022 UPDATED: February 2, 2022 10:52 IST

A powerful eruption on the Sun has hurled a solar magnetic storm towards Earth that will likely hit the planet on Wednesday. The explosion took place at the large sunspot region AR2936, which had become bigger in the last few weeks, releasing a Coronal Mass Ejection (CME) directed towards Earth.

The Center of Excellence in Space Sciences under the Kolkata-based Indian Institute of Science Education and Research said that the estimated time of arrival of the CME from the Sun is from February 2 late evening to February 3 morning. "Its speed of impact is estimated to be modest, however. We may expect minimal to moderate perturbations," the institution said.

Geomagnetic Storm Conditions Likely 2 - 3 February, 2022
published: Thursday, February 03, 2022 02:57 UTC

A G2 (Moderate) geomagnetic storm watch is in effect for the 2 February, 2022, UTC-day due to anticipated CME arrival. NOAA/SWPC Region 2936 produced an M1 flare (R1-Minor Radio Blackout) on 29 January at 6:32 pm ET (29/2332 UTC). This flare was associated with an asymmetric, full halo coronal mass ejection (CME) as observed in NASA/SOHO LASCO coronagraph imagery. Multiple analyses by SWPC forecasters indicated an approximate CME speed of 662 km/s and an at Earth arrival window as early as late 1 Feb to early 2 Feb ET. Forecast confidence in an Earth component to this CME is fair, while lower levels of confidence exist for intensity and arrival timing. Typically, CME arrival is first detected at the NOAA DSCOVR spacecraft (about 1 million miles away) before Earth arrival. Any geomagnetic storm conditions are likely to persist into 3 Feb at weakening levels, therefore, a G1 (Minor) geomagnetic storm watch is in effect for 03 February. Please continue to monitor our SWPC webpage for the latest information, forecasts, and updates regarding this activity.