This website is the digital version of the 2014 National Climate Assessment, produced in collaboration with the U.S. Global Change Research Program. For the official version, please refer to the PDF in the downloads section.
Lahars move rapidly down valleys like rivers of concrete. If you are on the floor of a valley that leads from a volcano and become aware of an oncoming lahar, seek high ground. Lahar is an Indonesian term that describes a hot or cold mixture of water and rock fragments that flows down the slopes of a volcano and typically enters a river valley.
As you move your finger closer to your face both eyes will converge as you move your finger away from your face your eyes will diverge. Saccades or saccadic eye movements are very fast jumps from one eye position to another. The velocity of saccades can be as large as 1000 deg/sec. To make a saccade or a series of saccades pick two objects as some distance from each other and look first at one then at the other.