1333: "Why Doesn't South America Have Hurricanes?"

HistoryPodcastScience
Written By JC

Interesting Things with JC #1333: "Why Doesn't South America Have Hurricanes?" – The water’s warm. The ocean’s the same. But hurricanes almost never hit South America. There’s a reason for that, and it’s not what most people think.

Curriculum - Episode Anchor

Episode Title
Why Doesn’t South America Have Hurricanes?

Episode Number
#1333

Host: JC

Audience: Grades 9–12, college intro, homeschool, lifelong learners

Subject Area: Earth Science, Meteorology, Physical Geography

Lesson Overview

Students will:

  • Define the key atmospheric and oceanic conditions necessary for hurricane formation.

  • Compare environmental conditions in the South Atlantic with those in hurricane-prone regions like the Gulf of Mexico and the Caribbean.

  • Analyze the role of latitude, Coriolis force, and wind currents in cyclone formation.

  • Explain the scientific and societal implications of Hurricane Catarina as a rare event.

Key Vocabulary

  • Coriolis force (kohr-ee-OH-lis) — The deflection of moving objects caused by Earth’s rotation, responsible for storm spin in hurricanes.

  • Subtropical high — A semi-permanent high-pressure zone in the mid-latitudes that helps steer weather systems, including hurricanes.

  • Easterly waves — Troughs of low pressure moving westward from Africa, often the seed for Atlantic hurricanes.

  • Warm pool — A large region of elevated sea surface temperatures crucial for tropical cyclone development.

  • Cold-core pattern — A type of storm formation initiated in cooler upper-atmosphere conditions, uncommon in tropical systems.

Narrative Core (Based on the PSF)

  • Open – The puzzle: same ocean, same temperatures, yet no hurricanes on South America’s northern coast.

  • Info – Scientific explanation of hurricane ingredients: warm water, instability, rotation.

  • Details – The mechanics that block hurricanes from forming or reaching South America—latitude, wind patterns, weak Coriolis effect.

  • Reflection – The danger of complacency; Hurricane Catarina as a reminder that rare doesn't mean impossible.

  • Closing – "These are interesting things, with JC."


Transcript

Interesting Things with JC #1333: "Why Doesn't South America Have Hurricanes?"

Stand on a beach in northern Brazil. Look east. That’s the same Atlantic Ocean that feeds monster storms into the Gulf of Mexico and up the U.S. coast. Same heat. Same time of year. But while folks in Florida are boarding windows, the coast here stays calm.

That’s not luck. It’s the way the planet works.

Hurricanes need three things to get going: warm ocean water, at least 80 degrees Fahrenheit, or 26.7 degrees Celsius, rising air to build the storm, and something to make it spin. That spin comes from Earth’s rotation, something called the Coriolis force. But here’s the catch, right near the equator, where northern South America sits, that spin weakens to almost nothing.

And that’s where Brazil, Guyana, Suriname, and French Guiana all sit, right near that center line. You can get storms, sure, but without that twist, they just won’t build into hurricanes.

Now, let’s say a storm does try to form. The winds push it northwest, not southwest. The Atlantic’s trade winds, along with a huge patch of high pressure out in the ocean, shove storms toward the Caribbean and the southeastern United States, not down toward South America. The odds are stacked against it.

And even if one fought the odds, there’s still the ocean to deal with. The warm water off Brazil’s coast isn’t deep enough or wide enough. A storm needs fuel, and in this case, the fuel tank’s too small.

So South America ends up in a strange spot, hot enough for hurricanes, close to where they start, but almost never hit.

Almost.

On March 27, 2004, a storm called Catarina hit the southern coast of Brazil. Winds topped 100 miles per hour, or 161 kilometers per hour. The eye was visible from satellites. It ripped into the state of Santa Catarina, and the country had no plan for it.

Why would they? Nothing like it had ever happened.

It formed far to the south, about 27 degrees below the equator, far enough for the Coriolis force to kick in again. It was unusual. Some scientists weren’t even sure what to call it. But it hit. People were hurt. Homes were lost. And the quiet broke.

For generations, folks in South America figured their spot on the map made them safe. Too close to the equator for hurricanes. Out of the storm path. No history, no worry.

Catarina changed that.

Because storms don’t care what we expect. And sometimes, the biggest risk is believing that if something hasn’t happened yet, it never will.

These are interesting things, with JC.


Student Worksheet

  1. Name and describe the three key ingredients needed for a hurricane to form.

  2. Why don’t hurricanes usually form near the equator?

  3. Explain how trade winds and the subtropical high influence storm direction in the Atlantic.

  4. Describe the factors that made Hurricane Catarina unusual.

  5. What lesson can be drawn from South America’s general hurricane silence?


Teacher Guide

  • Estimated Time: 45–60 minutes

  • Pre-Teaching Vocabulary Strategy: Create a hurricane ingredient chart with visual diagrams.

  • Anticipated Misconceptions:

    • All warm oceans produce hurricanes.

    • Hurricanes regularly strike any tropical coastline.

  • Discussion Prompts:

    • How do physical geography and Earth’s rotation shape weather?

    • Should countries that rarely face hurricanes still have storm preparedness plans?

  • Differentiation Strategies:

    • ESL: Use hurricane diagrams and bilingual glossaries.

    • IEP: Scaffold explanations with visuals and simplified text.

    • Gifted: Analyze atmospheric models of Catarina; present findings.

  • Extension Activities:

    • Compare Hurricane Catarina to a North Atlantic hurricane like Katrina or Irma.

    • Plot global cyclone tracks and discuss climate zone influences.

  • Cross-Curricular Connections:

    • Physics: Explore how angular momentum creates spin.

    • Geography: Map hurricane paths vs. ocean currents.

    • Data Science: Interpret cyclone formation datasets.


Quiz

  1. What prevents most hurricanes from forming near South America?
    A. Lack of water
    B. Weak Coriolis force
    C. High elevation
    D. Pollution
    Answer: B

  2. What is one effect of the subtropical high?
    A. It cools the ocean
    B. It deflects sunlight
    C. It steers hurricanes northwest
    D. It creates volcanoes
    Answer: C

  3. Where do most Atlantic hurricanes begin?
    A. Pacific Ocean
    B. South Pole
    C. West Africa
    D. Central America
    Answer: C

  4. Which storm made landfall in Brazil in 2004?
    A. Katrina
    B. Catarina
    C. Laura
    D. Sandy
    Answer: B

  5. Which of the following is NOT a required condition for hurricane formation?
    A. Warm ocean water
    B. Atmospheric instability
    C. Coriolis effect
    D. High elevation
    Answer: D


Assessment

  1. Summarize the conditions necessary for a hurricane to form and explain why South America’s coast typically lacks them.

  2. Describe how Hurricane Catarina defied expectations and what it teaches us about meteorological anomalies.

3–2–1 Rubric

  • 3 = Accurate, complete, thoughtful

  • 2 = Partial or missing detail

  • 1 = Inaccurate or vague


Standards Alignment

  • NGSS HS-ESS2-4 — Use a model to explain how variations in ocean temperature and Earth systems interact to drive atmospheric events like hurricanes.

  • NGSS HS-ESS3-1 — Analyze geoscience data to forecast weather and evaluate risks to humans.

  • CCSS.ELA-LITERACY.RST.11-12.2 — Determine central ideas of a scientific text and summarize key details.

  • CCSS.ELA-LITERACY.RI.9-10.3 — Analyze how the author unfolds an explanation or analysis of events.

  • IB MYP Sciences Criterion D — Evaluate the implications of scientific explanations in real-world scenarios.

  • Cambridge IGCSE Geography 0460/2.4 — Understand global weather processes and natural hazards, including tropical cyclones.


Show Notes

This episode of Interesting Things with JC examines a scientific mystery with global implications: Why does the coast of South America, despite warm ocean waters and a tropical climate, rarely experience hurricanes? The answer lies in a complex interplay of atmospheric dynamics, latitude, and Earth's rotation. Students and listeners learn about the Coriolis force, trade winds, subtropical high-pressure systems, and ocean heat profiles that prevent storms from spinning up or making landfall. The episode also discusses the landmark case of Hurricane Catarina in 2004, the only documented hurricane to strike Brazil. Catarina not only stunned meteorologists but revealed a deeper truth—rare events still demand preparedness. This story is not just about absence; it’s about how science explains what doesn't happen and why that matters.

References


JC https://jimconnors.org
Previous

1334: "1775: When Independence Became Inevitable"
Next

1332: "The Fighter Mafia"