Natural Phenomenon

Blood Falls

Blood Falls, named for its ruddy color, is not in fact a gush of blood from some unseen wound.

The color was initially chalked up to red algae, but a study in the Journal of Glaciology has uncovered its true origin using radar to scan the layers of ice from which the river pours.

Located in Antarctica’s McMurdo Dry Valleys, the falls pour forth from Taylor Glacier, and the liquid bubbles up from fissures in the glacier’s surface. The flow was previously a mystery, as the mean temperature is 1.4 degrees Fahrenheit (-17 degrees Celsius) and little glacial melting can be seen at the surface.

The longstanding mystery surrounding Antarctica's Blood Falls has finally been solved. The deep red falls were first discovered in Antarctica in 1911 where scientists noticed a river had stained the surrounding cliff of ice with a dark red color. Previously, they had believed it was due to algae discoloring the water, however that hypothesis was never verified.

According to the study, the makeup of the brine explains the fact that it flows instead of freezes.“The brine remains liquid within the subglacial and englacial environments through latent heat of freezing coupled with elevated salt content,” the study explains.

Iron Filled Salty Water

The lake under the glacier has an unusually salty consistency, and because saltwater has a lower freezing point than pure water and releases heat as it freezes, it melts the ice, enabling the rivers to flow.

This means that the glacier can support flowing water and also that this is the coldest glacier on Earth with constantly flowing water—though this water is so filled with iron that it looks like something else entirely.

The study also measured the amount of iron-rich brine in the river water and found the brine content increased as the measurements drew closer to the falls.

Water temperature and brine content were also found to be related: Cracks of various sizes in the glacier let brine into the glacier. Then the brine (pictured here in red to represent the amount of iron present in the water) begins to freeze, and the latent heat warms the ice around it, upping the brine concentration in the center of the cracks.