Above-freezing temperatures also led to overflow along the trail, a potentially dangerous situation where water has pushed up through the ice and refrozen, creating a weak top layer of ice that teams and mushers can break through.
Also, scientists at the Hong Kong Polytechnic University have been able to build a nano-thin layer of particles of titanium dioxide, a substance that reacts with sunlight to break down dirt and other organic material.
They built a thin layer, or "nanostructure, " using minute particles of titanium dioxide, a substance that reacts with sunlight to break down dirt and other organic material and can be coated on cotton to keep the fabric clean.