Solar flares on October 21, 2001
The most powerful solar flare in 24 hours
M2.5 (strong) flare - October 21 at 11:36 AM
Solar activity index
Value as of the end of the day on October 21, 2001
Solar X-ray emission over the past 2 days
Chart of solar X-ray emission (1-8 Å) from October 20, 2001 to October 21, 2001
Time zone — UTC+00
List of solar flares for October 21, 2001
The total number of solar flares of class C and higher — 11 flares
C class — 9 | M class — 2 | X class — 0
| Class | begin | max | end | region |
|---|---|---|---|---|
| C2.0 | 20:54 | 20:58 | 21:00 | — |
| C2.5 | 13:11 | 13:26 | 13:31 | 9670 |
| M2.5 | 11:12 | 11:36 | 11:48 | 9661 |
| C2.7 | 07:53 | 07:57 | 08:00 | — |
| C2.7 | 05:44 | 05:47 | 05:51 | — |
| M1.3 | 05:09 | 05:18 | 05:27 | — |
| C7.8 | 04:33 | 04:37 | 04:39 | — |
| C1.4 | 03:21 | 03:24 | 03:28 | — |
| C1.9 | 01:47 | 01:51 | 01:54 | — |
| C2.1 | 00:28 | 00:31 | 00:33 | — |
| C4.3 | 00:04 | 00:11 | 00:15 | 9672 |