An absorbing dynamometer acts as a load that is driven by the prime mover that is under test (e.g. Pelton wheel). The dynamometer must be able to operate at any speed and load to any level of torque that the test requires.
While some causes are obvious, such as hurricanes and snow melt, many are not. Heavy Rains: Cresting rivers, backed-up storm drains, or saturated ground can cause significant floods. Heavy rains can contribute to flash floods, which are the number one weather-related killer in the United States. A flash flood is a rapid flooding of low-lying areas in less than six hours. Heavy rains also increase the chance of mudflows, rivers of liquid, and flowing mud.
In 1889 a dam break upstream from Johnstown, Pennsylvania, released a 30-40 foot wall of water that killed 2200 people within minutes. Mountains and steep hills produce rapid runoff , which causes streams to rise quickly. Rocks and clay soils do not allow much water to infiltrate the ground. Saturated soil also can lead rapidly to flash flooding. Vacationing or recreating along streams or rivers can be a risk if there are thunderstorms in the area.