- Acre-footA measurement of water equal to 325,900 gallons,
or 1 acre of water 1 foot deep.
- Ari mutillakCommonly known as a "stone boy,"
it is a pile of rocks the sheepherders made to pass the time.
- BasaltDark igneous rock in lava flow.
- BatholithIgneous rock that has melted from pressures within
the earth. The rock then moves into or intrudes other rock formations.
- CalderaA large basin or depression resulting from a volcanic
- CirqueA hollowed-out area high on a mountain valley; typically
a place where glacial snow accumulates.
- CragA rugged rock formation jutting out from a cliff.
- CrevasseA deep chasm that forms within glaciers. They
can be more than 100 feet deep.
- CryptosporidiumA mysterious spore found in surface water
or rivers and lakes. It affects the human immune system, causing a flu-like
- ErraticsBoulders that are clearly out of place in meadows
or on mountaintops. Receding glaciers deposited them.
- FirefallFlaming embers that were pushed off the side of
Glacier Point to fall to the floor of Yosemite Valley. The practice was
stopped in the 1960s.
- FirnThe granular edge of snowfield that has remained frozen
through the summer but is not yet considered glacial.
- Garbage hillsRefuse piles where bears would feed and people
would watch. The ritual was stopped decades ago.
- GiardiaA protozoan found in surface water in many places.
It causes a serious illness with flu-like symptoms, such as vomiting and
- Glacial polishA granite surface ground smooth and clean
by a glacier.
- Hanging valleyUsually a river valley or small canyon that
has been cut across by a glacier, leaving it at a high elevation above
a larger valley floor. Several waterfalls in Yosemite Valley flow through
- HydroelectricThe creation of power through use of energy
of falling water to turn an electric generator.
- Hydraulic miningA technique used in the nineteenth century
in which miners would use a strong blast of water through a large hose
to strip away soil, rock, and other material from an area to bare a vein
of gold or silver.
- IgneousRock that was formed in a molten state or by fire,
such as volcanic rock.
- LimestoneFine-grained rock that comes from shells or reefs.
The rock is basically calcium carbonate.
- MetamorphicRocks that are changed over time by temperatures
and pressures into different kinds of rocks.
- MicroclimatesThe climate in a small area of a region,
usually affected by the local geography.
- MoraineThe debris and boulders left when a glacier passes
through an area. Usually moraines are deposited to the sides, lateral
moraine, or dropped when the glacier melts, terminal moraine.
- Old growthRefers to a forested area with trees that are
more than 40 inches in circumference. These trees are often hundreds of
years old, but size, not age, is more important in the old growth classification.
- OzoneGround-level gas created by the combination of sunlight
and chemicals from combustion sources, such as automobiles.
- Prescribed burnA fire intentionally set after assessing
the temperature, humidity, and wind conditions. The fire is intended to
burn off a buildup of vegetation.
- PumiceA type of lava that is porous and mostly glass.
In solid form, it is used in powdered forms as an abrasive.
- TaprootA deep root usually belonging to a plant that must
survive dry conditions.
- TarnA lake left by a receding glacier.
- Terminal lakeA body of water with no outlet to the ocean.
- TimberlineThe elevation where trees stop growing. It is
usually between 9,000 and 10,500 feet.
- TufaCalcareous deposits found in eerie rock forms at Mono
- TuffVolcanic ash that has been compacted to become rock.
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