G2moderate
The geomagnetic storm of 19 – 20 April 1978
On 19 – 20 April 1978 the Kp index reached 6−: a G2 (moderate) storm, with 15 hours at Kp 5 or more. At its peak the lights could be seen from 352,522 places in the atlas, down to about 50° magnetic latitude.
Kp 6−Peak Kp · 19 April 1978 18:00 UT
15Hours at Kp 5 or more
67Largest ap
Solar cycle 21Year 3 of solar cycle 21
Kp every three hours
56789
18 Apr19 Apr20 Apr21 Apr
Where the lights could be seen
At Kp 6− the lights reach 352,522 places of the atlas on the horizon and 116,237 overhead, down to about 50° magnetic latitude.
The largest towns that could see them
MoscowRussia · 13.3MSaint PetersburgRussia · 5.65MTorontoCanada · 2.79MChicagoUnited States · 2.73MMinskBelarus · 2MMontrealCanada · 1.9MNovosibirskRussia · 1.64MYekaterinburgRussia · 1.47MKazanRussia · 1.33MCalgaryCanada · 1.31MNizhny NovgorodRussia · 1.2MChelyabinskRussia · 1.18MSamaraRussia · 1.15MUfaRussia · 1.14MOmskRussia · 1.1MKrasnoyarskRussia · 1.09MPermRussia · 1.03MOttawaCanada · 1.02MEdmontonCanada · 1.01MStockholmSweden · 985kTyumenRussia · 872kLeedsUnited Kingdom · 822kWinnipegCanada · 750kSeattleUnited States · 737k