Evanston Winter Climate Activities

Level 4 ESL Lesson Packet: Analyzing the Climatology Report

Reading Selection: What is Changing About Winter in Evanston (Summary)

Research from the last 60 years shows that Evanston's winters are changing a lot because the region is getting about **3 degrees Fahrenheit warmer**. The number of days with **persistent cold**—when the temperature never goes above **40 degrees Fahrenheit** all day—is much lower than before. When the high temperature stays below **40 degrees Fahrenheit**, the ground cannot melt or thaw. In the past, especially the 1970s, winters brought **chronic** cold stress, meaning the low temperatures lasted for long, unbroken periods. This long-term cold is no longer the main problem.

A surprising effect called **decoupling** means that even with warming temperatures, the total amount of snow is **not** going down. Instead, the weather is showing high **volatility** (it changes strongly and quickly). Warmer air can hold more water. So, when it does snow, the snowstorms are fewer but much **higher-intensity** (very strong). The year-to-year swings in weather are often controlled by big global patterns like **teleconnections** (for example, El Niño or La Niña).

The city must now prepare for new **acute** risks—sudden, severe events. Less ice on Lake Michigan, combined with brief, extreme cold snaps like a **Polar Vortex**, increases the possibility of intense **Lake-Effect Snow (LES)** right near the lake. There are also more days where the temperature moves above and below the **32 degrees Fahrenheit** freezing point, which causes damaging **freeze-thaw cycles**. This repeated stress is destroying public **infrastructure** like roads and water pipes. City planning must now focus on quickly responding to these short, high-impact weather attacks instead of just managing long periods of cold.

Key Vocabulary and Concepts 🔑

Persistent Cold:
When the daily high temperature stays below **40 degrees Fahrenheit** for a long time, so the ground never thaws (melts).
Chronic:
Something that is **long-lasting** or happens over a long period of time (e.g., chronic back pain).
Acute:
Something that is **sudden** and **severe** (e.g., an acute fever; a sudden, strong snowstorm). This is the opposite of *chronic*.
Decoupling:
When two things that usually go together stop being connected. In the report, it means warming temperatures are no longer leading to less snow.
Volatility:
The quality of changing quickly and unexpectedly, usually with big differences (e.g., stock market volatility). Here, it refers to big, fast changes in winter weather.
Freeze-Thaw Cycles:
When the temperature moves back and forth across the **32 degrees Fahrenheit** freezing point, causing water to repeatedly freeze and melt. This process damages materials.

Introduction

These activities are based on the expert report: "Climatological Analysis of Persistent Cold and Snowfall Trends in Evanston, Illinois: 1965–2024." Please complete all seven sections. Pay special attention to vocabulary like **decoupling**, **chronic**, **acute**, and **volatility**.

Activity 1: True or False (T/F)

Write T (True) or F (False) for each statement based on the report.

  1. Persistent cold days in Evanston are decreasing due to a regional warming trend. (T/F: )
  2. The report found a strong long-term decline in seasonal snowfall totals over the 60-year period. (T/F: )
  3. The maximum temperature staying below **40 degrees Fahrenheit** is important because it prevents surface thawing. (T/F: )
  4. The 1970s winter profile was characterized by short, extreme cold snaps rather than long periods of cold. (T/F: )
  5. Less ice cover on Lake Michigan could *increase* the risk of intense Lake-Effect Snow (LES) in Evanston. (T/F: )

Activity 2: Multiple Choice (M.C.)

Select the best answer for each question.

1. The term **"decoupling"** in the report primarily means:

2. The main shift in Evanston's winter risk profile is from **chronic cold stress** to:

3. What is the primary cause of the destructive **freeze-thaw cycles** risk?

Activity 3: Matching Key Concepts

Match the term (1-5) on the left with its definition (A-E) on the right by writing the letter in the blank.

Terms

1. Persistent Cold

2. Lake-Effect Snow (LES)

3. Acute Risk

4. Teleconnections

5. Decoupling

Definitions

A. High-impact event happening quickly (e.g., a sudden, severe storm).

B. When the daily high temperature remains below **40 degrees Fahrenheit**.

C. Global weather patterns (e.g., El Niño) that influence winter storms.

D. Intense, localized snowfall caused by cold air moving over warmer lake water.

E. Snowfall totals remaining static despite persistent cold days decreasing.

Answers: 1. 2. 3. 4. 5.

Activity 4: Narrative Story (Reading Practice)

Read the story that summarizes the key findings of the report. The bold words are important vocabulary.

The Strange Winter of 2024

My grandmother, who has lived in Evanston since the 1970s, always talks about the old winters—long months of **chronic** cold. She remembers weeks where the maximum temperature stayed below **40 degrees Fahrenheit**. But the winter of 2024 was different. The long-term cold was gone, replaced by strange **volatility**. One week, it felt like spring. The next, a sudden **acute** Polar Vortex arrived, causing rapid thermal shock. We also dealt with intense **freeze-thaw cycles** that cracked the sidewalks and damaged the public **infrastructure**. It's a new kind of winter, demanding that the city quickly adapt to these intense, but short-lived, weather attacks.

Activity 5: Cloze Passage (Fill-in)

Use the words in the box to complete the passage. Use each word once.

acute decoupling chronic volatility infrastructure

Evanston's planning must shift from managing a **1.** ______ problem—long periods of sustained cold—to addressing **2.** ______ high-impact events. This change is due to the **3.** ______ of cold and snow trends, which creates higher **4.** ______ and puts more stress on **5.** ______ like roads and pipes.

Answers: 1. 2. 3. 4. 5.

Activity 6: Sentence Completion

Complete the sentences based on the information in the report (try to use your own words).

  1. The regional winter warming trend means Evanston must now manage more risks related to .
  2. Because warmer air holds more moisture, new snow events are likely to be fewer but .
  3. The city's planning must prioritize mitigating the risks associated with a changing snowfall .
  4. Infrastructure planning is now focused on protecting roads and pipes from the damage caused by frequent .
  5. The high year-to-year swings in snowfall are often attributed to global atmospheric circulation patterns, or .

Activity 7: Dialogue Practice (15 Lines)

Practice this conversation between Martha (a long-time Evanston resident) and Leo (a newcomer). Notice how they use vocabulary from the report.

MARTHA (1): You must be new here. Our winters have totally changed since the seventies.
LEO (2): It seems so strange. The report mentioned a **3 degrees Fahrenheit** warming trend.
MARTHA (3): That's the **persistent cold** that's gone. We used to have weeks of freezing weather.
LEO (4): So, why do we still get such **volatile** snow totals? I thought warmer meant less snow.
MARTHA (5): That's the **decoupling**. Less cold, but the atmosphere holds more moisture now.
LEO (6): Ah, so when it *does* get cold, the snow is extremely heavy and intense.
MARTHA (7): Exactly. Especially with the **Lake-Effect Snow**. It's hyper-local near the shore.
LEO (8): So the risk is less **chronic** cold stress and more **acute** disasters?
MARTHA (9): That’s what the climatologists say. We went from managing long-term cold...
LEO (10): ...to managing short, fast, high-impact events. That makes sense.
MARTHA (11): Right. Like the **Polar Vortex** cold snaps, but they don't last as long as they did in the eighties.
LEO (12): And all the back-and-forth temperatures—the **freeze-thaw cycles**—must be terrible for the roads.
MARTHA (13): It is. They need to spend money upgrading the **infrastructure** to handle it.
LEO (14): I guess even if the average temperature is higher, we still need to be ready for the worst snow.
MARTHA (15): Always. That's the new normal for winter in Evanston.

Answer Key

Activity 1: True or False

  • 1. **T**
  • 2. **F** (The report says there is no strong long-term decline)
  • 3. **T**
  • 4. **F** (The 1970s had long periods of cold, representing *high persistence*)
  • 5. **T**

Activity 2: Multiple Choice

  • 1. **b)** Warming temperatures are no longer strongly linked to lower total snowfall.
  • 2. **c)** Acute, high-impact events like sudden blizzards or floods.
  • 3. **b)** More days where the temperature hovers around the **32 degrees Fahrenheit** freezing point.

Activity 3: Matching Key Concepts

1. **B**, 2. **D**, 3. **A**, 4. **C**, 5. **E**

Activity 5: Cloze Passage

1. **chronic**, 2. **acute**, 3. **decoupling**, 4. **volatility**, 5. **infrastructure**

Activity 6: Sentence Completion (Sample Answers)

  • 1. Acute, high-impact events / high-intensity rain and snow events.
  • 2. Higher-intensity / concentrated into shorter timeframes.
  • 3. Character / risk of intense Lake-Effect Snow (LES).
  • 4. Freeze-thaw cycles.
  • 5. Teleconnections.

Activity 4 and 7 are reading/speaking practice and do not have a separate answer key.