This is a single exposure.
The weather at Lofoten changes dramatically! The day before it was raining, dark and cloudy while the next day it was one of clearest I have seen. Infect at night I could clearly see the Milkyway up in the starry sky! This helped me in planning this shot.
Scouted this location while driving around the same day afternoon and decided to come back at night to shoot the Aurora Borealis.
EXIF: Nikon D850, Tamron SP 15-30 2.8 Di VC Lens, 15mm, F/2.8, 20 Sec, ISO-3200