 Known since the early 1900s, the caves were thought to have disappeared altogether in the mid-1940s, yet in 1978 cavers measured of passageways in glacier caves there, and it was then considered the longest glacier cave system in the world.The Paradise Ice Caves collapsed and vanished in the 1990s, and the lower lobe of the glacier which once contained the caves has also vanished entirely between 2004 and 2006.Glacier caves may be used by glaciologists to gain access to the interior of glaciers.