WEATHER

The hurricane currently battering the Bahamas exploded in intensity two days before forecasters predicted. (Nat Geo News)

See what makes hurricanes tick by making one yourself—with our Forces of Nature interactive!

Teachers, scroll down for a quick list of key resources, including today’s MapMaker Interactive map and our Educator of the Week’s guidance on teaching about natural hazards.

Discussion Ideas

• According to Nat Geo News, “A drop in wind shear and an unusually warm pool of water in the ocean have contributed to Joaquin’s growth into a powerful hurricane.” What is wind shear?
  • Wind shear describes changes in wind speed and direction over a set distance.
  • Weather Underground puts it in context: “In general, wind shear refers to any change in wind speed or direction along a straight line. In the case of hurricanes, wind shear is important primarily in the vertical direction—from the surface to the top of the troposphere. The troposphere is the region of the atmosphere that our active weather is confined to, and extends up to about 40,000 feet altitude (a pressure of about 200 mb) in the tropics in summer. Hurricanes fill the entire vertical extent of the troposphere, and are steered by the average wind through this layer.”

• How does a drop in wind shear strengthen a hurricane?
  • According to Nat Geo News, “Joaquin’s slow-moving nature means it has more time to power up, which helps to account for the storm’s explosive growth.”

• How does warmer water strengthen a hurricane?
  • According to Nat Geo News, “Hotter sea surface temperatures means more water evaporating into the atmosphere, loading a hurricane with more energy . . . The hurricane will lose steam once it’s separated from warm water.”

• What are some natural hazards associated with hurricanes? Look at bookmark 4, “Characteristics of Hurricanes,” in our great Forces of Nature interactive, for some help.
  • winds
  • floods and flash floods
  • landslides
  • storm surges. Storm surges are usually the most dangerous part of a hurricane. A storm surge is “a bulge of water built up in front of a cyclone or hurricane courtesy of its winds. It’s the number one killer in hurricanes, said Kerry Emanuel, an atmospheric scientist at MIT. ‘That’s what killed people in Katrina, it’s what killed people in Sandy and in Haiyan.’”

• Most models predict Hurricane Joaquin will not make a powerful landfall in the United States. So why do most meteorologists predict such a wet weekend for the East Coast?
  • According to Nat Geo News, “moisture from the storm will be pulled into a low pressure system heading towards the east coast. That will still give communities along much of the Atlantic seaboard a good soaking.”

Watch Joaquin, as well as the low-pressure system blanketing the East Coast, in this typically terrific video from the good folks at NASA and their GOES East satellite.

TEACHERS’ TOOLKIT

Nat Geo: What Makes Hurricanes Like Joaquin Tick?

Nat Geo: Forces of Nature (hurricanes is the third icon)

Nat Geo: Hurricane Joaquin interactive map

Nat Geo: Teaching about Natural Disasters

National Hurricane Center: Hurricane Joaquin

Weather Underground: Hurricane Joaquin