An updated rate-of-spread clock

Several years ago, Blank and Simard (1983) described an electronic timer, frequently referred to as a rate-of-spread (ROS) clock—a relatively simple instrument used in measuring fire spread. Although other techniques for measuring rate of spread are available (such as data loggers), the basic ROS clock remains a valuable and relatively inexpensive tool. However, several items described in the original article have changed. Therefore, we are describing an updated version of the ROS clock.