Heat Dome

Context

Recently, the US based weather agency said heatwaves in general are becoming more frequent because of the heat dome and climate change.

About Heat Dome

It is a weather phenomenon that occurs when a persistent region of high pressure traps heat over an area.

The high-pressure system acts like a lid, preventing warm air from rising and causing the air below to warm up.

Formation

Heat domes can arise in still and dry summer conditions, when a mass of warm air builds up, and the high pressure from the Earth’s atmosphere pushes the warm air down.

The air is then compressed, and as its net heat is now in a smaller volume, it increases in temperature.

As the warm air attempts to rise, the high pressure above it acts as a dome, forcing the air down and causing it to get hotter and hotter, resulting in increased pressure below the dome.

Correlation with Jet Streams

Typically, heat domes are tied to the behaviour of the jet stream, a band of fast winds high in the atmosphere that generally runs west to east.

Normally, the jet stream has a wavelike pattern, meandering north and then south and then north again.

When these meanders in the jet stream become bigger, they move slower and can become stationary. That’s when heat domes can occur.

Impact

Heat domes can severely impact human health, increasing the risk of heat illnesses and deaths as people cannot cool down properly.

It can last anywhere from days to weeks.

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