Situational Analysis Report on the Space Weather Events Occurred during 11–12 November 2025: X-Class Solar Flare and CME-Driven Geomagnetic Storm
Background
The solar flare is a large eruption of electromagnetic radiation from the Sun that lasts from minutes to hours. In terms of energy output, solar flares are classified into five classes, A, B, C, M, and X, with each class representing tenfold more power. Solar flares of the X class are the strongest, and their intensity is determined by the number following the X.
A geomagnetic storm is a significant disruption of Earth’s magnetosphere that occurs when there is an effective transfer of energy from the solar wind into the surrounding space environment of Earth. Storms that result from these conditions are associated with solar coronal mass ejections (CMEs), with 1 billion tons or more of plasma from the sun arriving at Earth with its magnetic field embedded. Most CMEs arrive at Earth within several days, but some of the most intense storms have been observed to arrive within 18 hours.
Solar flares can lead to radio blackouts, degradation of navigation systems, and satellite uplink/downlink disturbances. CME-driven geomagnetic storms can cause power-grid disruptions, satellite damage and orbital changes, communication failures, and enhanced auroral activity.
Source of the Events
On November 11, 2025, an X1.5-class solar flare erupted from an active solar region AR2474 with a peak around 16:04 UTC, producing intense X-ray radiation followed by a fast Earth-directed coronal mass ejection (CME). This outburst is a series of intense flares from AR2474, which also produced an X1.7 flare on November 9 and an X1.2 on November 7. The CME, traveling at an estimated speed of approximately 1,569 km/s, interacted with CMEs released on November 9–10, resulting in a compounded geomagnetic disturbance at Earth.
On November 12, at around 18:50 UTC, the CME associated with this solar flare arrived at Earth. This arrival caused a sudden increase in the measured solar wind speed to 1089 km/s. The global geomagnetic conditions reached severe storm levels (G4 NOAA scale) on November 13 between 08:09 UTC and 09:56 UTC after which they decreased to moderate levels.
X-class solar flares and the associated CME-driven geomagnetic storms primarily affect technology and infrastructure, while posing no direct physical harm to humans on Earth’s surface due to the protective shielding of the atmosphere and the geomagnetic field.
The D-Region Absorption Product addresses the operational impact of the solar X-ray flux and SEP events on HF radio communication. Long-range communications using high frequency (HF) radio waves (3 – 30 MHz) depend on reflection of the signals in the ionosphere. Radio waves are typically reflected near the peak of the F2 layer (~300 km altitude), but along the path to the F2 peak and back the radio wave signal suffers attenuation due to absorption by the intervening ionosphere. The D-Region Absorption Prediction model is used as guidance to understand the HF radio degradation and blackouts this can cause.
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