Geomagnetic solar storms have caused beautiful Northern lights around the upper hemisphere this week, but also managed to ground planes in Sweden on Wednesday.
In Southern and central Sweden, the solar storms interfered with air traffic control systems, and no planes were able to take off for more than an hour, reports CBC.
The issues did not spread to neighbouring countries.
A spokesperson for the civil aviation authority told CBC it was unclear why their systems were so greatly impacted, as something similar had not happened since 1999.
According to The Local Sweden, heavy delays were expected Wednesday afternoon and evening.