Major Sunspot Group 4366: X-Class Flare Risk & Solar Activity Forecast

The Sun is currently exhibiting an unusually high level of activity, with a large sunspot region, designated AR4366, responsible for a barrage of solar flares, including several of the most powerful classifications. This activity poses a potential risk to Earth’s technological infrastructure, though the most significant impacts are expected to occur later this week.

A Hyperactive Sunspot Region

Sunspot region 4366 first appeared on January 30, 2026, and has rapidly become a focal point for space weather forecasters. Since its emergence, it has produced at least six X-class solar flares, the most intense category of solar flares. On February 1, 2026, the region unleashed an X8.1-class flare – the strongest flare observed since October 2024, when an X9 flare was recorded. This flare ionized the upper layer of Earth’s atmosphere, causing a shortwave blackout across the South Pacific Ocean, impacting ham radio operators in Australia and New Zealand.

The intensity of these flares is notable. Solar flares are categorized as A, B, C, M, and X, with each letter representing a ten-fold increase in energy output. Within each category, a numerical scale from 1 to 9 is used to further refine the intensity, though X-class flares can exceed this scale. The recent activity from AR4366 demonstrates the upper end of this scale, with flares reaching X8.1 and X4.2.

Recent Flare Activity and Coronal Mass Ejections

As of today, February 4, 2026, AR4366 has continued its intense activity, producing an X4.2 flare just after 7 a.m. ET. The X8.1 flare on February 1st was accompanied by a coronal mass ejection (CME) – a massive expulsion of plasma and magnetic field from the Sun’s outer atmosphere. Scientists at NOAA’s Space Weather Prediction Center (SWPC) are tracking this CME as it travels toward Earth.

In addition to the X-class flares, AR4366 has also emitted dozens of M-class flares in a short period. Specifically, 23 M-class flares were recorded within a 24-hour span. On February 3rd, an X1.5 flare peaked at 14:08 UTC, causing an R3 (strong) radio blackout over the south Atlantic Ocean east of Brazil. Further flares continued on February 4th, with another X flare, an X4.2, occurring at 6:13 a.m. CST.

Potential Impacts on Earth

When CMEs impact Earth’s magnetosphere, they can cause geomagnetic storms. These storms can induce dazzling auroras, but also have the potential to disrupt or damage critical infrastructure. Specifically, intense geomagnetic storms can affect power grids, satellites, and radio communications. Models currently suggest that the bulk of the solar material from the CME associated with the X8.1 flare will pass by Earth on Thursday evening, though the magnetosphere could still experience a glancing blow.

The sunspot region is described as having grown rapidly, becoming nearly half the size of the Carrington sunspot, which was responsible for the largest geomagnetic storm in recorded history in 1859. The current situation is being closely monitored by the SWPC, and further updates are expected as the CME approaches Earth. The region is also moving toward a “geoeffective position,” meaning any future CMEs it emits are more likely to be directed toward our planet.

Flare Activity Summary

Over the past 24 hours (from 11 UTC February 3 to 11 UTC February 4), solar activity has been very high. In addition to the X1.5 flare, 15 M-class flares and 10 C-class flares were observed, all originating from AR4366. Specific M-class flare times include: February 3: M7.2 at 14:56 UTC; M2.1 at 16:36 UTC; M2.5 at 18:08 UTC; M2.0 at 22:50 UTC; M3.5 at 23:09 UTC. February 4: M1.2 at 1:10 UTC; M1.4 at 1:39 UTC; M1.4 at 1:55 UTC; M2.1 at 2:30 UTC; M4.9 at 2:39 UTC; M2.1 at 3:55 UTC; M1.8 at 9:20 UTC; M3.1 at 10:12 UTC; M1.5 at 10:46 UTC and M1.6 at 10:55 UTC.