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+

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+

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

Stormy Space Weather is no fun for HF

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:

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:

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:

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