The entire western United States has come under the grip of a sweltering heatwave, which began last week. The scorching temperatures and dry conditions are a result of a heat dome centred over California.
About Heat Dome:
- It is a weather phenomenon where a high-pressure system in the atmosphere traps warm air like a lid on a pot, for an extended period of time.
- As the warm air is not able to rise upward, the sky remains clear — clouds are formed under the opposite circumstances as the rising warm air cools down, and the water in it condenses out.
- The high-pressure system allows more sunlight to reach the earth, which results in more warming and drying of soil. This leads to less evaporation and reduces the likelihood of the formation of rain clouds.
- The longer the heat dome stays in one place, the warmer conditions can get with every passing day. While heat domes cause heat waves, they can occur without heat domes as well.
What is the role of the jet stream?
- A heat dome’s formation is tied to the behaviour of the jet stream — an area of fast-moving air high in the atmosphere that usually helps move weather systems along the Earth’s surface.
- Typically, the jet stream has a wave-like pattern that keeps moving from north to south and then north again.
- When these waves get bigger and elongated, they move slowly and sometimes can become stationary. This is when a high-pressure system gets stuck in place and leads to the occurrence of a heat dome.
UPSC Prelims Practice Question
Ques : With reference to “heat dome” seen in the news recently, consider the following statements:
1. It occurs when an area of low-pressure traps cold air over a region.
2. The heat dome’s formation is related to the behaviour of the jet stream.
Select the correct statement using the codes given below:
a) 1 only
b) 2 only
c) Both 1 and 2
d) Neither 1 nor 2
Ans : b)
