EASC 2310 Lesson 32: Extreme Weather Flashcards

Flashcards of key terms and concepts from the lecture about extreme weather.

What is the student expected to do regarding sever weather events?

Investigate different types of severe weather events such as a hurricane, tornado, or flood and explain that some events are more likely than others in a given region.

What three ingredients are required for all thunderstorm formations?

Moisture, Instability (Unstable Air), and Lift (A Lifting Mechanism).

What is the typical source of moisture for thunderstorms, and what plays a large role in how much moisture is added to the atmosphere?

Oceans are the typical source; water temperature plays a large role.

Where do warm and cool ocean currents typically occur along continents?

Warm ocean currents occur along the east coasts of continents, while cool ocean currents occur along the west coasts of continents.

When is air considered unstable?

Air is considered unstable if it continues to rise when given a nudge upward or continues to sink if given a nudge downward.

What characterizes an unstable air mass?

Warm moist air near the surface and cold dry air aloft.

What are the methods that accomplish a difference in air density?

Convergence (Low Pressure), Differential Heating, Terrain, Fronts, Dry Lines

What are the stages of a thunderstorm cell's life cycle?

Towering Cumulus (Developing) Stage, Mature Cumulus Stage, Dissipating Stage

What happens during the Towering Cumulus (Developing) Stage of a thunderstorm?

A cumulus cloud begins to grow vertically, with air dominated by upward-moving, warm, moist air currents called updrafts.

What characterizes the Mature Cumulus Stage of a thunderstorm, and why is it considered the most dangerous stage?

The storm has considerable depth, with strong updrafts and downdrafts coexisting; it is the most dangerous stage.

What happens during the Dissipating Stage of a thunderstorm?

The downdraft cuts off the updraft; the storm no longer has a supply of warm moist air to maintain itself and dissipates.

What are the different types of thunderstorms?

Single-Cell Thunderstorm, Multi-Cell Thunderstorm, Squall Line, Supercell

What characterizes Single-Cell Thunderstorms?

Typically driven by heating (convection) on a summer afternoon, with a short life and usually not severe.

What is a multi-cell thunderstorm?

A common thunderstorm type in which new updrafts form along the leading edge of rain-cooled air (the gust front).

What is a squall line?

A group of storms arranged in a line, often accompanied by squalls of high wind and heavy rain.

What is a supercell thunderstorm?

A long-lived and highly organized storm feeding off a rotating updraft.

What is a tornado?

A violently rotating column of air descending from a thunderstorm and in contact with the ground.

When is the peak of tornado season in the US, and where do more tornadoes strike?

The peak of the tornado season is April through June, with more tornadoes striking the central US.

Which area in the United States has the most hail?

Nebraska, Colorado, and Wyoming.

What is hail?

Solid ice that forms when updrafts in thunderstorms carry raindrops upward into extremely cold areas of the atmosphere.

What are the hazards of lightning strikes?

They kill people and animals, cause fires, and damage buildings and electrical systems.

What is thunder, and what causes it?

The sharp or rumbling sound that accompanies lightning, caused by the intense heating and expansion of the air along the path of the lightning.

What is a gust front?

It is a line of dangerously gusty winds created when a downdraft from a raining thunderstorm hits the ground and spreads out.