A Massive Heat Dome Hits America: The Prelude to a Dangerously Intense Summer — Challenges of Adaptation and Mitigation Posed by the Heat Dome

1. Introduction

A "heat dome," a kind of atmospheric "lid," is settling over the central to eastern United States, leading to one of the most dangerous heatwaves on record. The National Weather Service (NWS) has issued its highest warning, describing the situation as "extremely dangerous." For several days to a week, daytime temperatures are expected to exceed a perceived 40°C, with "tropical nights" where temperatures do not drop.livescience.com

Initial Reactions on Social Media

On the official NWS Chicago X account, a two-part tweet stated, "A heat index exceeding 100°F (38°C) is expected for at least three consecutive days. Regular hydration and air conditioning are essential." The hashtag #ILwx #HeatDome quickly trended, with personal accounts such as "The commuter train feels like a sauna" and "I finished walking the dog before dawn" being shared.chicagotonight.wttw.com

2. Mechanism of the Heat Dome and Characteristics of the Current Event

A heat dome is a phenomenon where strong high pressure in the upper atmosphere traps hot air near the surface. Imagine it as a lid on a pot. When high pressure stagnates, convection is suppressed, resulting in fewer clouds and direct sunlight. Additionally, evaporating groundwater increases humidity, making it difficult for the body to cool itself through sweating. The current dome formed over the central plains of North America and is moving eastward, supported by unseasonably warm Pacific sea surfaces (post-La Niña) and an "Omega blocking" pattern in the upper air flow.livescience.comwashingtonpost.com

3. Regional Impact

4. Health and Social Impact

• Heat-related Deaths: The deadliest natural disaster in the U.S. is heatwaves, with over 800 deaths annually. This time, high humidity prevents sweat from evaporating, increasing the risk of heatstroke → multi-organ failure.chicagotonight.wttw.com

• High Nighttime Temperatures: If temperatures do not drop below 25 °C, sleep disturbances and cardiovascular strain accumulate.There are reports of a shortage of oral rehydration solutions at 24-hour drugstores.

• Power Peak: ERCOT (Texas) and PJM (Eastern Grid) are considering "conservation requests" anticipating a surge in demand. In the event of a power outage, homes could turn into "heat sickrooms," posing a threat to lives.

5. Ripple Effects on Infrastructure and Economy

• Roads and Railways: Speed restrictions due to asphalt softening and rail expansion. During last year's extreme heatwave in Canada, rail temperatures reached 70 °C.

• Agriculture: Concerns over "silking heat stress" coinciding with the corn pollination period. A 5% yield reduction scenario in the grain belt is beginning to reflect in the futures market.

• Labor Productivity: At outdoor construction sites, the requirement for a 15-minute break per hour in accordance with OSHA standards is expanding. Cases of project delays due to increased labor costs have been reported.

6. Climate Change and Long-term Trends

According to the EPA, the occurrence of large heatwaves in the U.S. has tripled, and their duration has doubled compared to the 1960s. The IPCC AR6 asserts that without anthropogenic GHGs, the current probability of extreme heatwaves in North America would be less than one-tenth. While the current heat dome requires individual causal assessment, it is clear that global warming has elevated the "baseline warming." livescience.com

7. Voices Spread on SNS and Hashtag Analysis

8. Measures to Take (Individual and Community)

1. Hydration and Electrolytes: Drink 1–2 glasses per hour without waiting for thirst.

2. Cooling Zones: Check in advance for municipal Cooling Centers, libraries, malls, etc.

3. Night Ventilation: Open windows only when outside temperature is lower than room temperature.

4. Outdoor Work: Take a 15-minute break if WBGT exceeds 28°C (OSHA recommendation).

5. Neighbor Check: Reach out to the elderly, those living alone, and outdoor workers.apnews.com

9. Administrative and Policy Trends

• Emergency Declarations: Seven states including NY and IL have declared heat emergencies. Free distribution of bottled water and ice packs.

• Relaxation of Power Regulations: Temporarily easing environmental regulations to ensure peak power generation.

• Long-term Measures: Expanding urban forestry, mandating cool roofs, and creating climate adaptation funds.
  The Washington Post estimates "220 million people will be affected in the next 10 days," and the reintroduction of the "Heat Response Act" is being considered as a political priority.washingtonpost.com

10. Summary and Outlook

The current heat dome is likely just the "beginning of this summer." The risk of atmospheric wave stagnation due to global warming is increasing across the North American continent, and there is a fear that heatwaves of the same or greater magnitude will repeatedly strike. Along with individual-level measures, it is necessary to proceed "simultaneously" with cooling urban infrastructure, designing systems to protect the socially vulnerable, and reducing greenhouse gas emissions.

Reactions on SNS

Wow, the heat dome in the US is insane! Hope everyone stays safe. #HeatDome

— UserName (@username) October 1, 2023

Many reactions have been shared on X (formerly Twitter) and other social media platforms regarding such extreme weather phenomena. Comments like "The heat dome in the US is truly terrifying! Hope everyone stays safe." can be seen.

Additionally, opinions such as "Seeing the heat dome in the US makes me think about how climate change is impacting the world globally." reflect a growing international environmental awareness.