Current Conditions

Radio Blackout Levels (R-Scale)

Level Severity Impact Description X-Ray Class
R0 NONE No HF radio blackout < M1
R1 MINOR Minor HF degradation M1 – M4
R2 MODERATE Limited HF blackout M5 – M9
R3 STRONG Wide area HF blackout X1 – X9
R4 SEVERE HF blackout on most sunlit side X10 – X19
R5 EXTREME Complete HF blackout X20+

Solar Radiation Storm Levels (S-Scale)

Level Severity Impact Description Proton Flux (pfu)
S0 NONE No radiation storm – Normal HF propagation < 10
S1 MINOR Minor polar cap absorption – Slight HF degradation 10 – 99
S2 MODERATE Moderate polar cap absorption – HF degradation over polar routes 100 – 999
S3 STRONG Strong polar cap absorption – HF blackout over polar regions 1,000 – 9,999
S4 SEVERE Severe polar cap absorption – Extended HF blackout 10,000 – 99,999
S5 EXTREME Extreme polar cap absorption – Complete HF blackout polar regions 100,000+

Geomagnetic Storm Levels (G-Scale)

Level Severity Impact Description Kp Index
G0 NONE Quiet conditions – Normal HF propagation Kp < 4
G1 MINOR Minor storm – Slight HF degradation at high latitudes Kp = 5
G2 MODERATE Moderate storm – HF fading at higher latitudes Kp = 6
G3 STRONG Strong storm – HF intermittent, degraded navigation Kp = 7
G4 SEVERE Severe storm – HF widespread blackout, navigation disrupted Kp = 8
G5 EXTREME Extreme storm – HF complete blackout, navigation failure Kp = 9

GeoMagnetic Storms

Making sense of buzz

Stormy Space Weather is no fun for HF 

📡 For HAM Radio Operators 

When you see R, S, or G flashing on a solar weather monitor, here’s what it means to your rig:

  • R (Radio Blackouts) – These are triggered by strong solar X-ray flares. When the level hits R2 (moderate) or higher, the D-layer of the ionosphere over daylight paths becomes highly ionized, soaking up your HF signals—especially 20 meters and down. Expect shortwave silence for minutes to hours.

  • S (Solar Radiation Storms) – These relate to high-energy protons blasting through space. At S2 (moderate) and above, expect increased noise on polar paths and degraded propagation over the poles. They can also fry satellite electronics.

  • G (Geomagnetic Storms) – These are the big ones for HF. A G3 (strong) or higher storm means major magnetic turbulence in the ionosphere. Signals bounce unpredictably, MUFs fluctuate, and entire HF bands can vanish or become distorted.

Severity levels range from:

  • 0 (none) – Smooth sailing.

  • 1 (minor) – Occasional dropouts or weak band openings.

  • 2 (moderate) – QSB increases, and skip gets weird.

  • 3+ (strong to extreme) – Expect HF chaos.

(What/Where/Why of Disturbances):

  • R Levels (X-ray-induced Radio Blackouts)
    These originate from solar flares, typically measured by GOES satellites in the 1–8 Å X-ray range. A rapid increase in soft X-ray flux enhances ionization in the D-region of the ionosphere. These effects are instantaneous on the dayside and degrade signal integrity on HF bands.

  • S Levels (Solar Radiation Storms)
    Driven by solar energetic particle (SEP) events, typically protons >10 MeV, these storms are monitored by GOES-E and GOES-W spacecraft. High S-levels cause polar cap absorption (PCA) events, disturb HF communications in polar regions, and pose risks to aviation and satellite systems.

  • G Levels (Geomagnetic Storms)
    Caused by coronal mass ejections (CMEs) or high-speed solar wind streams hitting Earth’s magnetosphere. These interactions drive geomagnetic disturbances detectable via magnetometers globally. They result in auroral activity, perturb F-layer stability, and alter HF propagation paths through increased ionospheric currents and density gradients.

Each level corresponds to Dst index depression, Kp values, and magnetometer deflections, with classification from:

  • G0 (none) up to G5 (extreme) geomagnetic events.

In a Nutshell for the Radio Ham:

  • R is for Radio Blackouts – Happens fast when the Sun pops a big flare. Your HF band might go silent, especially on the sunlit side. Watch for R2 and up.

  • S is for Solar Radiation Storms – Particles flying at Earth mess up polar HF paths. Above S1, your signal might struggle to make it over the pole.

  • G is for Geomagnetic Storms – Earth’s magnetic field is shaking. Big G means weird skip, dropped signals, and vanishing bands. G3+? Might be a good day to fix antennas instead.

Severity goes from:

  • 0 = None
  • 1 = Minor
  • 2 = Moderate
  • 3 = Strong
  • 4 = Severe
  • 5 = Extreme

The higher the number, the more likely your 20m DX just turned into static.

Please register for continued access

Click Here

You have Successfully Subscribed!