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Standardized Precipitation Evapotranspiration Index
The Standardized Precipitation Evapotranspiration Index (SPEI) is a multiscalar drought index, proposed in 2010, that measures drought from the climatic water balance of precipitation minus potential evapotranspiration over chosen time scales.
Standardized Precipitation Index
The Standardized Precipitation Index (SPI) is a drought index expressing precipitation over periods like 3 or 12 months as a standardized departure from local climatological norms.
Stanford Watershed Model
The Stanford Watershed Model is a pioneering computer program developed at Stanford University by Norman Crawford and Ray Linsley that simulates streamflow from precipitation, becoming the ancestor of the EPA's HSPF model.
Star sand
Star sand (星砂, hoshizuna) is beach sand composed of the star-shaped, millimeter-sized calcareous shells of the foraminifer Baculogypsina sphaerulata, found most often on the beaches of Okinawa, Japan.
State of Fear
State of Fear is a 2004 techno-thriller novel by Michael Crichton, published by HarperCollins, in which eco-terrorists stage natural-looking disasters to convince the public climate change is a crisis.
Static stability
Static stability, also called hydrostatic or vertical stability, is the tendency of a fluid at rest, such as the atmosphere, to resist or favor vertical displacement through buoyancy.
Station model
A station model, also called a surface-plotting model, is a standardized arrangement of weather symbols plotted around a circle on a weather map, in wide use since the 1920s.
Stationary front
A stationary front, also called a quasi-stationary front, is a boundary between warm and cold air masses moving slowly or not at all, often bringing prolonged rain and flooding.
Staurolite
Staurolite is a brown iron–aluminum silicate mineral, named from the Greek stauros for cross, best known for its cross-shaped penetration twins and as an index mineral of medium-grade metamorphic schists.
Steering flow
Steering flow is the large-scale environmental wind field that determines the movement of a tropical cyclone, averaged through the troposphere's depth, and it underlies most track forecasting.
Stemflow
Stemflow is precipitation intercepted by a plant canopy that runs down stems, branches, and trunks to the soil, concentrating water and nutrients at the plant's base.
Stephanie Abrams
Stephanie Abrams, born 1978, is an American television meteorologist from Wellington, Florida, who joined The Weather Channel in 2003 and co-hosts AMHQ and the weekend climate show Pattrn.
Stepped-frequency microwave radiometer
The stepped-frequency microwave radiometer (SFMR) is an airborne instrument that measures ocean surface wind speed and rain rate in tropical cyclones from NOAA and Air Force reconnaissance aircraft.
Stereophotogrammetry
Stereophotogrammetry reconstructs 3D surface geometry from pairs of overlapping photographs taken from two camera positions, producing point clouds and digital elevation models used to measure terrain, glaciers, ocean waves, and clouds.
Stibnite
Stibnite is an antimony sulfide mineral with the formula Sb₂S₃ and the predominant ore mineral of antimony, forming bladed orthorhombic crystals in hydrothermal deposits, often with gold.
Stillwater Complex
The Stillwater Complex is a layered igneous intrusion, about 2.7 billion years old, exposed along the northern Beartooth Mountains in south-central Montana and hosting the J-M Reef.
Sting jet
A sting jet is a narrow, transient airstream of strong wind descending from the mid-troposphere in some extratropical cyclones, producing localized damaging surface gusts over 100 mph.
Stishovite
Stishovite is a dense high-pressure polymorph of silica first identified in 1961 by Sergei Stishov, occurring naturally at meteorite impact sites like Meteor Crater, Arizona.
Stomatal conductance
Stomatal conductance measures how readily water vapor diffuses out of a leaf through stomatal pores, set by pore aperture and guard cell turgor, and is a key parameter in earth system models.
Storativity
Storativity, also called the storage coefficient, is a dimensionless measure of the water volume an aquifer releases or absorbs per unit surface area per unit change in hydraulic head.
Storegga Slide
The Storegga Slide is a giant submarine landslide off mid-Norway, whose failure about 8,200 years ago generated a tsunami that struck coasts around the North Sea.
Storm
A storm is a disturbed state of the atmosphere marked by severe weather such as strong winds, heavy rain, or lightning, from single thunderstorms to vast cyclones.
Storm Amy
Storm Amy was the first named storm of the 2025/26 European storm season, bringing record October winds, widespread power outages, and one death to Ireland and the UK.
Storm Arwen
Storm Arwen was a European windstorm that struck the UK and Ireland on 26 to 27 November 2021, killing three people and cutting power to over 1 million homes.
Storm Boris (2024)
Storm Boris was a slow-moving low-pressure system that brought record rainfall and severe flooding to Central and Eastern Europe in September 2024, killing 27 people.
Storm Chasers (TV series)
Storm Chasers is an American documentary reality television series that premiered on the Discovery Channel in 2007, following storm chase teams as they intercepted tornadoes in Tornado Alley.
Storm chasing
Storm chasing is the pursuit of severe thunderstorms and tornadoes by vehicle, usually for observation, photography, science, or media coverage, focused on the central United States in spring.
Storm Ciara
Storm Ciara, called Sabine in Germany and Elsa in Norway, was an extratropical cyclone that brought severe gales and flooding to Europe in February 2020.
Storm Ciarán
Storm Ciarán was the third named storm of the 2023/24 European windstorm season, bringing damaging winds and heavy rain to Britain, the Channel Islands, and France.
Storm damage
Storm damage: destruction from winds, hail, tornadoes, storm surge, and flooding. Covers damage mechanisms, Enhanced Fujita rating, assessment methods, insurance allocation, FEMA assessments, and billion-dollar loss trends.