G4severe
The geomagnetic storm of 13 September 1957
On 13 September 1957 the Kp index reached 9−: a G4 (severe) storm, with 18 hours at Kp 5 or more. At its peak the lights could be seen from 700,645 places in the atlas, down to about 44° magnetic latitude.
Kp 9−Peak Kp · 13 September 1957 06:00 UT
18Hours at Kp 5 or more
300Largest ap
Solar cycle 19Year 4 of solar cycle 19
Kp every three hours
56789
12 Sep13 Sep14 Sep
Where the lights could be seen
At Kp 9− the lights reach 700,645 places of the atlas on the horizon and 413,512 overhead, down to about 44° magnetic latitude.
The largest towns that could see them
MoscowRussia · 13.3MNew York CityUnited States · 8.8MLondonUnited Kingdom · 8.8MSaint PetersburgRussia · 5.65MMelbourneAustralia · 5.35MBerlinGermany · 3.7MKyivUkraine · 2.95MTorontoCanada · 2.79MBrooklynUnited States · 2.74MChicagoUnited States · 2.73MQueensUnited States · 2.41MParisFrance · 2.1MMinskBelarus · 2MMontrealCanada · 1.9MHamburgGermany · 1.87MWarsawPoland · 1.86MManhattanUnited States · 1.69MNovosibirskRussia · 1.64MPhiladelphiaUnited States · 1.6MUlaanbaatarMongolia · 1.52MThe BronxUnited States · 1.47MYekaterinburgRussia · 1.47MKharkivUkraine · 1.42MPragueCzechia · 1.4M