Iceblink is the reflection of light off distant ice fields and onto the underside of low-hanging clouds. It's important to keep an eye out for iceblink if you happen to be navigating the Arctic Ocean.
Iceblink creates a distinct yellowish or whitish glow on the horizon. Before the invention of radar and satellite imagery, polar explorers relied on iceblink to navigate safely. Because ice reflects more light than the open ocean, creating bright spots on the horizon, sailors could steer clear of those areas of iceblink, heading for darker patches known as "water sky" instead. But reading the iceblink can be tricky: When there are temperature inversions (cold air trapped beneath warm air), iceblink might create mirages, making distant ice floes appear like massive, towering walls of ice or mythical ice castles in the sky.