Major X8.7 flare erupts from Region 3664 — the strongest solar flare of Solar Cycle 25

A powerful solar flare measuring X8.7 erupted from Active Region 3664 — currently located off the west limb of the Sun — at 16:51 UTC on May 14, 2024. The event started at 16:46 and ended at 17:02 UTC.

• This is the strongest solar flare of Solar Cycle 25 and the 16^th X-class flare since May 1.
• Today’s X8.7 is also the strongest flare since X9.3 on September 10, 2017 — the strongest solar flare of Solar Cycle 24.

A Type II (estimated velocity of 497 km/s) and IV radio emissions were associated with the event — indicating a strong coronal mass ejection (CME) was produced.

In addition, a 10cm Radio Burst (tenflare), lasting 7 minutes and with a peak flux of 1 100 sfu was associated with this event. A 10cm radio burst indicates that the electromagnetic burst associated with a solar flare at the 10cm wavelength was double or greater than the initial 10cm radio background. This can be indicative of significant radio noise in association with a solar flare. The noise is generally short-lived but can cause interference for sensitive receivers including radar, GPS, and satellite communications.

Radio emissions were forecast to be most degraded over the Americas, East Pacific, and Northern Atlantic at the time of the flare.

Coronagraph imagery of the CME was not available at the time of press. However, the location of this region does not favor Earth-directed CMEs anymore.

The opposite is true for solar radiation storms. In fact, periods of S1 – Minor and S2 – Moderate solar radiation storms were registered since 13:50 UTC on May 13 and there is a good chance radiation storm will continue over the next 24+ hours.

Interestingly, just over 40 minutes after today’s X8.7 flare — at 17:48 UTC, an M4.4 flare erupted from a new region emerging on the SE limb — AR 3682.

A large CME was associated with this event but the location of the region still doesn’t favor Earth-directed CMEs. However, this can be an early signal of continued increased solar activity over the next week or so.

The Sun has produced more than 100 M-class and 16 X-class flares since May 1, and a series of Earth-directed CMEs — some of which merged into one powerful Cannibal CME and produced historic G5 – Extreme geomagnetic storm on May 10 and 11.

The last time Earth experienced a G5 – Extreme geomagnetic storm was in October 2003 — dubbed the Halloween Storms of 2003. These storms resulted in power outages in Sweden and damaged transformers in South Africa. Surprisingly, they occurred 2 to 3 years after solar maximum.

This time, NOAA reported some minor power grid irregularities and impacts on high-frequency communications and GPS, while Elon Musk reported his Starlink satellites are ‘under a lot of pressure but holding up so far.’

G1 – Minor to G2 – Moderate geomagnetic storming is likely on March 14 due to weak positive polarity coronal hole high speed stream (CH HSS) coupled with CME produced on May 12.

Featured image credit: X8.7 solar flare on May 14, 2024. Credit: NASA SDO/AIA 304, Helioviewer, The Watchers