saturation 100 percent humidity, the maximum amount of moisture the air can hold.
snow blindness temporary blindness caused by bright sunlight reflecting off snow.
snowblink a yellowish or whitish glow over a snowfield.
snowflake classification the seven basic types of snowflake are star, hexagonal plate, needle, column, capped column, spatial dendrite, and irregular.
thundersnow a snowstorm, often heavy, with thunder and lightning.
whiteout zero visibility caused by blizzard conditions.
rivers and streams
Acheron in Greek and Roman mythology, the river of woe, one of the five rivers surrounding Hades.
alluvial fan the debris consisting of silt, gravel, and rocks deposited by rivers along the foot of mountains, creating a fanlike series of ridges.
alluvium any debris eroded by or deposited by a river, such as silt, gravel, rocks, and boulders.
aquifer groundwater, or any natural underground reservoir of water.
bar a ridgelike deposit or accumulation of sand or silt in or along a river.
bed the bottom of a river.
benthos plants and animals inhabiting the bottom of a river.
bight a curve or bend in a shoreline.
billabong an Australian term for a waterway filled with water only during rainy season.
boil a water current that "boils" or upwells into a convex mound.
braided river a river divided into several intertwining branches or "braids" created by a series of built- up sandbars or banks.
branch one division of a forked river or a smaller river joining a larger one; a tributary.
brook a small stream.
cataract a waterfall.
channel the deepest part of a river.
chute a descending and steep and narrow passage of water.
creek a small, shallow stream.
delta a triangular-shaped island of deposited sediment forming downstream at a river's mouth.
detritus particles of decaying plants and animals used as a source of food by many aquatic animals.
eddy the backward-rotating current found behind rocks or other obstructions above the surface.
estuary the body of water affected by tides, where the mouth of a river meets the sea.
feeder any branch that joins into a larger watercourse.
fjord a long arm or river of ocean water running between high cliffs or banks.
floodplain any flat area that may be flooded by a river when it overflows its banks.
fluvial referring to rivers or things found in or formed by rivers.
ford a shallow portion of a river allowing people to cross on foot.
fork portion of a river that branches into two parts.
freshet an overflow of a stream due to heavy rains or melting snow.
gradient the rate of descent over a section of river, usually measured in feet per mile.
haystacks the large, standing waves that form at the bottom of rapids wherever the current is decelerating.
headwaters small brooks and streams that join to form a river.
hummock a flow of current forming a hump over a rock.
hydraulics the science of water in motion.
hydrologist one who studies the dynamics of water. hydrophobia the fear of water. kill a creek.
levee an embankment built along the shore of a river to protect from flooding.
meander to wind or wander aimlessly, as a river.
milldam a dam constructed across a river to raise its water level and pressure in order to turn a mill wheel.
millrace the river or channel of water used to turn a mill wheel.
moraine a huge deposit of boulders, gravel, and silt left behind by a receding glacier and responsible for damming up some rivers to form lakes.
oxbow a noose-shaped loop of water forming along the side of a river, sometimes separating from the river entirely to form a pond.
pitch a section of rapids that is steeper than surrounding sections.
pool slow-moving deep water.
race a portion of a river that is moving swiftly, especially due to a narrowing.
rapids swiftly moving white water broken by rocks.
riffles a shallow stream with small ripples caused by a bed of cobbles, rocks, and gravel.
rill a tiny stream or brook.
rip a wave or waves caused by a collision of currents in swiftly moving water.
riparian referring to a riverbank area.
riverhead a river's source.
rooster a standing wave with a crest that turns back on itself, sometimes known to swamp canoes or rafts.
runnel a tiny brook or stream.
runoff water from rain or melted snow coursing over the ground or through sewers into a waterway.
shoal a shallow area surrounded by deeper water.
sluice an artificial channel for conducting water.
souse hole a foamy, violently turbulent eddy; also known as a white eddy.
spring a water source issuing from underground.
Styx the river of hate, one of the five rivers in Greek mythology surrounding Hades.
tongue a smooth passage of black water flowing between two rocks or obstructions, often leading into a chute.
torrent a rough and swiftly flowing stream.
tributary a stream or river that "contributes" its water to a larger river or body of water.
vortex a whirlpool.
watershed the area from which a river receives its water.
whirlpool water pulled by current forces into a rotating motion that exerts a powerful draw on surrounding water or debris.
white water rapids.
rocks and gems
acroite a colorless variety of tourmaline.
adularescent having a lustrous, bluish-white hue, as a moonstone.
adularia a variety of moonstone, characterized by a semitranslucent and whiteish-blue hue.
agate a type of porous quartz that forms several different colors.
agglomerate a pyroclastic rock consisting mostly of volcanic bombs.
alexandrite a variety of quartz that appears blue- green when viewed outside and reddish-purple under indoor or artificial light.
alluvium sand, mud, gravel, and rocks carried and deposited by rivers.
almandine a type of common garnet characterized by colors ranging from red or purplish red to orange- brown.
amber yellowish, translucent fossilized resin from coniferous trees.
American ruby a ruby in name only, actually a pyrope garnet.
amethyst a type of purple or sometimes mauve- colored quartz.
ametrine a type of quartz containing both amethyst and citrine colors.
ammolite the shell of an ammonite, an ancient sea mollusk, that has been pressurized, fossilized, and mineralized.
amygdule a cavity in igneous rock filled with secondary minerals, such as calcite or quartz.