U.S. Environmental Protection Acid Rain pH Scale: U.S. Environmental Protection Agency (EPA)
North America Avalanche Danger Scale: National Avalanche Center (NAC) / Avalanche Canada
The Hong Kong Observatory (HKO) Color-Coded Rainstorm/Cloudburst Warning System Scale: Hong Kong Observatory (HKO)
North Indian Ocean Tropical Cyclone Intensity Scale: India Meteorological Department (IMD)
Pandemic Severity Index (PSI) Scale: U.S. Centers for Disease Control and Prevention (CDC)
Palmer Drought Severity Index (PDSI) Scale: National Center for Atmospheric Research (NCAR)
Torro International Hailstorm Intensity Scale: Tornado and Storm Research Organisation (TORRO)
Air Quality Index (AQI) Haze Scale: U.S. Environmental Protection Agency (EPA)
The Heat Index Heatwave Scale: National Weather Service (NWS)
Saffir-Simpson Hurricane Scale: National Hurricane Center (NHC) / NOAA
Severe Storms & Regional Scales
The NWS Rip Current Threat Index Scale: National Weather Service (NWS) / NOAA
CMA Sandstorm/Dust Storm Scale: China Meteorological Administration (CMA)
The NOAA Solar Flares/Storm Scale: NOAA Space Weather Prediction Center (SWPC)
The Super Fog (AFI) Scale: U.S. Forest Service (USFS) / Southern Research Station [Achtemeier, FI]
The Enhanced Fujita (EF) Tornado Scale: Wind Science and Engineering Research Center / NOAA
The Tsunami Alerts Scale: National Tsunami Warning Center (NTWC) / NOAA
The CMA Typhoon Scale: China Meteorological Administration (CMA)
Winter Storm Severity Index (WSSI): National Weather Service (NWS)
Northeast Snowfall Impact Scale (NESIS): National Centers for Environmental Information (NCEI)
Geological, Ecological & Humanitarian Scales
The International Volcanic Health Hazards Network (IVHHN) Ashfall Thickness & Impact Scale: International Volcanic Health Hazards Network (IVHHN)
The Richter Earthquake Scale: California Institute of Technology (Caltech)
Sussex Magnitude Famine Scale: Institute of Development Studies (IDS), University of Sussex [Howe & Devereux]
The New Jersey Department of Environmental Protection (NJDEP) Harmful Algal Bloom (HAB) Scale: The New Jersey Department of Environmental Protection (NJDEP)
Volcanic Explosivity Index (VEI): United States Geological Survey (USGS) / Smithsonian Institution
Forest Fire Danger Index (FFDI) Wildfire Scale: Commonwealth Scientific and Industrial Research Organisation (CSIRO)