Descriptionary

stalagmite conical calcium carbonate formation standing on the floor of caves; the counterpart of a stalactite.

sump an underwater passage in a cave; also known as a syphon.

troglobite any animal specially adapted to live in caves.

troglodyte a caveman.

troglophile any animal who inhabits a cave but may not be specially adapted to live there, such as a bat.

CLOUDS

altocumulus elliptical globular masses, forming individually, in groups, or in bands between 6,500 and 23,000 feet; also known as sheep or woolpack clouds.

altostratus bluish or grayish white sheets covering most or all of the sky between 6,500 and 23,000 feet.

anvil the flat top of a spreading cumulonimbus cloud, which resembles an anvil.

arcus any low, horizontal cloud seen at the leading edge of a thunderstorm, but particularly a roll or shelf cloud.

banner cloud a stationary, bannerlike plume seen frequently over the lee side of a mountain.

barber pole slang for any curving cloud striation, resembling the stripes on a barber pole, caused by updrafting in a thunderstorm.

ceiling the height of the lowest clouds.

cirriform thin, wispy clouds appearing at high altitude.

cirrocumulus rippled or banded clouds, often referred to as a "mackerel sky," forming between 16,000 and 45,000 feet.

cirrostratus high, thin, white veils covering all or most of the sky between 16,000 and 45,000 feet.

cirrus detached, feather or tufted clouds form­ing between 16,000 and 45,000 feet; also known as mares's tails.

clinometer device used to measure the height of clouds.

cloud seeding a technique in which various chemi­cals, especially silver iodide and dry ice, are dispersed into clouds via aircraft or rockets in an attempt to produce precipitation.

cloud tag

cloud fragment. Also known as scud, fractus.

congestus a towering, cauliflower-like cumulus cloud.

contrails vapor trails left by aircraft.

cumuliform any mound or dome-shaped cloud or one that towers.

cumulonimbus towering clouds arising from cumu­lus 2 to 5 miles in height, yielding rain and sometimes thunderstorms. The thunderstorm cloud itself is called a thunderhead.

cumulus individual cloud masses vertically domed with a cauliflower-like appearance; associated with fair weather.

debris cloud at the base of a tornado, a rotating cloud of dust and debris.

eye wall the cloud band immediately surrounding a hurricane, the most intense area of the storm.

fractocumulus a ragged-looking cumulus cloud.

fractus any broken-off cloud fragment. Also known as scud.

funnel cloud a funnel-shaped cloud descending from a cumulus or cumulonimbus cloud, technically becoming a tornado only when debris and dust can be seen churning below it at ground level.

halo apparent circle around the sun or moon, caused by the refraction of sunlight by ice crystals in high, thin cirrus or cirrostratus clouds.

incus the anvil-shaped top of a thunderhead.

mammatocumulus cloud with extreme billowing or boiling appearance, accompanying severe thunder­storms and tornado conditions.

nephology the study of clouds.

nephoscope a device that measures the height and speed of clouds.

nimbostratus thick, dark gray, and shapeless cloud sheets associated with steady precipitation, forming between 6,500 and 23,000 feet.

noctilucent cloud a cloud that appears to "glow" at night, caused by reflected sunlight below the horizon.

roll cloud associated with a thunderstorm, a low, horizontal, tube-shaped cloud.

scud ragged patch broken off from main cloud by the wind.

shelf cloud associated with a thunderstorm, a low, horizontal, wedgelike cloud.

stratocumulus

heavy rolls or globular masses arranged in bands covering most of the sky, forming between 0 and 6,500 feet.

stratus continuous, layerlike cloud deck, with no individual units, forming between 0 and 6,500 feet.

updraft rising moist, warm air that condenses into cumulus and cumulonimbus clouds.

virga wisps or trails suspended from clouds, often composed of rain that evaporates before reaching the ground.

deserts

alluvial fan the deposits of alluvial material, such as rocks and silt, that fan out at a mountain base or slope.

alluvium deposits of sand, silt, gravel, or rocks transported by water and laid down near stream or lake beds or around the base of mountains.

arroyo a dried-up stream or riverbed.

badlands a barren area where soft rocks or clays became eroded, creating ridges, mesas, channels, and gullies.

bajada the overlapping area of two or more alluvial fans, creating a wide expanse of deposited debris.

barchan a crescent-shaped sand dune, created by a one-directional wind.