That part of snow melt that reaches stream channels as runoff.

A coating of ice, generally clear and smooth. formed by the freezing of supercooled water on a surface.

A cup anemometer with its shaft mechanically coupled to a magneto.

Integrated Flood Observing and Warning System. National Weather Service flood warning program.

The state of the atmosphere, mainly with respect to its effects upon life and human activities. As distinguished from climate, weather consists of the short-term (minutes to months) variations of the atmosphere.

A motorlike device containing a rotor and a stator and capable of converting an angular position into an electrical signal, or an electrical signal into an angular position. When several synchros are correctly connected, all of the rotors will align thems ...

A point (or line) on a scale used for reference or comparison purposes. In calibration of meteorological thermometers, for example, the fiducial points are 100

In nautical terminology, a contraction for "weather glass" (a mercury barometer).

An instrument which measures the scattering function of particles suspended in a medium in order to determine the visual range through the medium. See visibility meter.

A type of photoelectric photometer used to measure high-altitude winds on the assumption that stellar scintillation is caused by atmospheric inhomogeneities being carried along by wind near the tropopause level.

The ratio of the existing amount of water vapor in the air at a given temperature to the maximum amount that could exist at that temperature. Usually expressed in percent.

An instrument used for the determination of the electrical conductivity of the atmosphere.

An absolute temperature scale with the degree of the Fahrenheit scale and the zero point of the Kelvin scale. The freezing point of water equals 491.69

An instrument used for measuring geometric angles. See radio direction-finder.

See hydrologic accounting.

A metallic element of atomic weight 200.6 1, unique (for metals) in that it remains liquid under all but very extreme temperatures.

The difference between temperature measurements taken at two significant levels above the ground. Temperatures at 10 and 40 meters are commonly used.

Precipitation falling from a cloud, usually in wisps or streaks, but evaporating before it reaches the ground.

Dihydrogen oxide, molecular formula H2O.

An instrument used to measure and record earthquake vibrations and other earth tremors.