final exam w&s

What is meant by a 100 year flood?

It is a flood that has a 1 in 100 chance of occurring in any single year.

Urban sprawl's impact on flooding

Urban sprawl reduces the ground's ability to absorb water, increasing the likelihood and magnitude of floods.

Flash flood

A flash flood occurs with little or no warning, is rapid in nature, mostly affects small rivers and streams, and often results in fatalities.

Widespread floods

Widespread floods involve a large amount of rainfall over several days, can last a week or more, and result in greater economic losses.

Coastal floods

Coastal floods can result from tsunamis and increases in ocean height due to storm surges.

Watershed

An area that drains into a river or stream.

Stage (in the context of flooding)

The height of the water surface of a river.

Floodstage

The level at which the river rises enough to cause damage to property.

Floodplains

Land that has been repeatedly flooded.

Levees

Embankments designed to prevent the flow of water onto a floodplain.

Tropical cyclone

A weather pattern that can deliver extreme amounts of rainfall.

Frontal overrunning

Precipitation occurring north of a stationary weather front that does not move very much.

Pineapple express (atmospheric rivers)

Moisture from near Hawaii brought to California, flowing like a river in the air.

Flash flood watch vs warning

A watch means flooding is possible; a warning means flooding has already occurred.

Severe thunderstorm characteristics

Includes hail 1-inch or larger, wind speeds of 58 mph or greater, and the possibility of tornadoes.

Stages of an ordinary thunderstorm

Cumulus stage: updrafts and warm moist air

mature stage: thunder and lightning, air is rising and sinking

dissipating stage: downdrafts and rain begins to spread throughout the air cutting energy and moisture off

4 elements of the development of a thunderstorm

1. source of moisture

2. unstable atmoshpere

3. mechanism to trigger updrafts

4. vertical windshear

What is a supercell thunderstorm?

A large, rotating single-cell thunderstorm capable of causing severe weather like tornadoes.

Greatest density of lightning flashes

Occurs along central Florida and the South Atlantic coast due to high humidity.

Definition of lightning

Lightning is an electrical discharge during a storm. easier for electrons to move creating lightning; it is usually 3 miles long, 1 inch in diameter, and can reach temperatures of 54,000 degrees Fahrenheit.

Conductors vs Insulators

Conductors allow electric charges to flow easily (e.g., metal, water); insulators do not allow electric currents to pass through.

Stepped leader

The initial phase of a lightning stroke, where multiple streams of electrons create a channel downwards.

What causes the sound of thunder?

Thunder is created by sound waves generated by the rapid expansion and contraction of air heated by lightning.

Safety tips during lightning storms

Stay indoors, avoid electrical appliances, and minimize ground contact if outdoors.

Hurricane Sandy impact

Caused significant beach erosion (30-40 feet) and affected 24 states, with only New York receiving funding for damages.

Tornado Xenia

The only alerts for the tornado were from schools and the weather channel; Ohio now leads in communication stations.

squall lines

lines of thunderstorms that border along the front

mesoscale convective systems

scale of meteorolgy going from small to big storms. difficult to see on radar because the difference in temperature between the air masses is small.

relationship between thunderstorms and global climate change

length of winter will reduce, early spring means early thunderstorm season, weakened jet stream means less supercell storms.

protons, electrons, charges, and currents

protons: positively charged particles

electrons: negatively charged particles

charges & currents: electrons make up majority of the currents because they move easily

Stepped Leader

develops because the electrons take the path of least resistance downwards, multiple streams or channels of electrons coming to give a forked appearence.

return stroke

positive stream meets the negative down flowing current creating a powerful return stroke. important because the flash of lightning happens.

dart leader

ionized path or channel that allows another large stream of elecrtons to move down.

2nd return stroke

ensures that current can enable the lightning flash to move across the ionized channel

how is heat lightning formed

from thunderstorms far away. the light travels but not the sound