Category |
Effect |
Physical measure |
Average Frequency |
|
---|---|---|---|---|
Scale |
Descriptor |
Duration of event will influence severity of effects
|
||
Radio Blackouts |
GOES X-ray peak brightness by class and by flux* |
Number of events when flux level was met; (number of storm days) |
||
R 5 |
Extreme |
HF Radio:Complete HF (high frequency**) radio blackout on the entire sunlit side of the Earth lasting for a number of hours. This results in no HF radio contact with mariners and en route aviators in this sector. Navigation: Low-frequency navigation signals used by maritime and general aviation systems experience outages on the sunlit side of the Earth for many hours, causing loss in positioning. Increased satellite navigation errors in positioning for several hours on the sunlit side of Earth, which may spread into the night side. |
X20 |
Less than 1 per cycle
|
R 4 |
Severe |
HF Radio: : HF radio communication blackout on most of the sunlit side of Earth for one to two hours. HF radio contact lost during this time. Navigation: Outages of low-frequency navigation signals cause increased error in positioning for one to two hours. Minor disruptions of satellite navigation possible on the sunlit side of Earth. |
X10 |
8 per cycle
|
R 3 |
Strong |
HF Radio: Wide area blackout of HF radio communication, loss of radio contact for about an hour on sunlit side of Earth. Navigation: Low-frequency navigation signals degraded for about an hour. |
X1 |
175 per cycle |
R 2 |
Moderate |
HF Radio: Limited blackout of HF radio communication on sunlit side, loss of radio contact for tens of minutes. Navigation: Degradation of low-frequency navigation signals for tens of minutes. |
M5 |
350 per cycle |
R 1 |
Minor |
HF Radio: Weak or minor degradation of HF radio communication on sunlit side, occasional loss of radio contact. Navigation: Low-frequency navigation signals degraded for brief intervals. |
M1 |
2000 per cycle |
* Flux, measured in the 0.1-0.8 nm range, in W·m-2. Based on
this measure, but other physical measures are also considered.
** Other frequencies may also be affected by these conditions.