Opalescent Geyser, Norris Geyser Basin, YNP.

Hot spring located at the northwest end of Porcelain Terrace. The water is neutral-to-alkaline, and rich in Cl. Water rising into the pool is boiling (~92 ºC). The temperature is measured at ~10 cm depth, toward the edge of the pool. The water level in the pool appears to have remained stable in recent years. The site is off-limits to the public and is surrounded by unstable thermal ground.

Water temperature is measured beneath the pool surface. Temperature increases may reflect increased inflow of thermal water. Sudden decreases in temperature could be a result of a drop in water level beneath that of the temperature probe. This will usually result in large diurnal (24-hour) variations as the probe measures air temperature instead of water temperatures. Smaller diurnal variations are normal in pools.