Thor is thinning out Santa’s herd in Norway.

A single bolt of lightning killed more than 300 reindeer that were huddled together during a severe thunderstorm Friday that ravaged the mountainous Hardangervidda plateau in southern Norway.

“They were lying there dead in a fairly concentrated area. Reindeer are pack animals and are often close together. During a heavy thunderstorm, they may have gathered even closer together out of fear,” Knut Nylend, of the Norwegian Nature Inspectorate, told the local news agency NTB.

Norwegian officials found 323 lifeless reindeer carcasses, 70 of which were calves, strewn across a field during a routine inspection of the area, according to the Norwegian Environment Agency.

Some of the animals will be tested at the Norwegian Veterinary Institute to determine the cause of death.

“We’re heard about animals being struck by lightning and killed, but I don’t remember hearing about lightning killing animals on this scale before,” Nylend said.