Geography 1700 Chapter 9 Part 3 of 4

Geography 1700Chapter 9

Part 3 of 4

A recent Geography 1700 student found a Web page that claimed “Super-Storm Sandy” created 39 feet of flood on Long Island, NY in 2012.

This imaginary storm expected storm surge up to 21 feet above normal sea level.

Do flood protection features (like levees) sometimes fail?

Are levees reliable? Is the Mississippi River under control?

If you wait too long, will your escape close behind you?

The “Super Dome” in New Orleans. – 2005 Kathrina

Figure 9.8A picture is worth 1,000 words.

Figure 9.A

This guy spent a month in jail for just riding-out the storm at home.

Soldiers thought he was a “looter.”

Took a month to figure it out. Storms create confusion.

Most of these areas have been rebuilt or

repaired.

We are gamblers and people usually sell their homes in

4-7 storms.

The time period between severe storms is usually longer than that.

Scenes like this are common in tsunami waves and cyclones.

Water levels rise very a few minutes, hours or

days.

Hurricane Katrina – 2005The city has been slowly sinking below sea level. Levees and dikes were never

expected to outlast such storms. Repairs have not yet been completed.

A hurricane may contain hundreds of thunderstorms that are individually as big as those commonly seen in Utah.

Hurricanes may contain dozens of thunderstorms large enough to produce a tornado.

“Hot Towers” in a hurricane represent rising air that contains vast amounts of heat hidden in water vapor. They may rise to more than 60,000 feet and still

contain enough heat to keep rising.

Figure 9.15Hurricane - Notice the high walls around the “eye” of the storm.

Jet StreamsMeridional vs Zonal

Flow

When the jet stream provokes storms by

mixing cool/dry with warm/wet - conflict

High

Low

Notice that is eastward-moving storm is typical - counter-clockwise air in the mid-latitudes

Frontal Weather

• Cold fronts

Frontal Weather

• Occluded front

Life of a Midlatitude Cyclone

Notice that in a mid-latitude cyclone, cold and warm air don’t mix at first.

As Coriolis force helps turn the air, mixing begins as warm, humid air lifts over cooler, drier air that is more heavy.

Rising air provokes condensation, precipitation and strong winds.

At the end, warm air is temporarily stable above cold air below.

Warm, wet air rises above cool/dry air classic “frontal” storm.

Here we see how the jet stream (with storm track) helps pull low and high pressure cells toward each other.

The difference between warm/wet and cool/dryhelps produce rising air, high wind, precipitation, hail, lightning.

Figure 9.18a

Figure 9.18b

Figure 9.18c

Figure 9.18d

Figure 9.18e

Figure 9.18f

Figure 9.21