In Norway, archaeologists from a program called Secrets of the Ice are searching for items that melt out of ice patches. Pictured, a team member holds a 1,400-year-old arrow. Glacier Archaeology Program Oppland

A very rare type of arrowhead was found in 2018, near melting ice on a reindeer-hunting site. It is 1,500 years old and was discovered with its wooden arrow shaft, which can also be seen in the picture. Glacier Archaeology Program Oppland

This packhorse cranium is 300 years old. Archaeologists have found remains of dead packhorses where an old mountain route crossed the ice. Glacier Archaeology Program Oppland

Glacial archaeologists pack artifacts after a day of fieldwork in a glaciated mountain pass. Johan Wildhagen/Palookaville.

Some sites are so large that the archaeologists have to survey them for weeks to collect all the finds. In such cases, a base camp is established near the site, like this camp below the ice patch at 1,650 meters. Glacier Archaeology Program Oppland

Prehistoric and medieval skis have melted out of the glacial ice. This ski is radiocarbon-dated to around 700 AD. Glacier Archaeology Program Oppland

Reindeer will move onto snow and ice on hot summer days to avoid pestering insects. The ancient hunters knew this and hunted the reindeer on the ice, which is why so many hunting tools were lost in the snow on these sites. Glacier Archaeology Program Oppland