G1minor
The geomagnetic storm of 21 – 22 October 1973
On 21 – 22 October 1973 the Kp index reached 5+: a G1 (minor) storm, with 15 hours at Kp 5 or more. At its peak the lights could be seen from 317,119 places in the atlas, down to about 50° magnetic latitude.
Kp 5+Peak Kp · 21 October 1973 18:00 UT
15Hours at Kp 5 or more
56Largest ap
Solar cycle 20Year 9 of solar cycle 20
Kp every three hours
56789
20 Oct21 Oct22 Oct23 Oct
Where the lights could be seen
At Kp 5+ the lights reach 317,119 places of the atlas on the horizon and 96,450 overhead, down to about 50° magnetic latitude.
The largest towns that could see them
MoscowRussia · 13.3MSaint PetersburgRussia · 5.65MTorontoCanada · 2.79MChicagoUnited States · 2.73MMontrealCanada · 1.9MNovosibirskRussia · 1.64MYekaterinburgRussia · 1.47MKazanRussia · 1.33MCalgaryCanada · 1.31MNizhny NovgorodRussia · 1.2MChelyabinskRussia · 1.18MUfaRussia · 1.14MOmskRussia · 1.1MKrasnoyarskRussia · 1.09MPermRussia · 1.03MOttawaCanada · 1.02MEdmontonCanada · 1.01MStockholmSweden · 985kTyumenRussia · 872kWinnipegCanada · 750kSeattleUnited States · 737kMississaugaCanada · 718kOsloNorway · 718kHelsinkiFinland · 694k