The state of California in the USA is witnessing heavy rains for the past week in its southern parts, raising concerns of landslides in the region. Experts have attributed this excessive rainfall to the Atmospheric rivers. It is likely to bring positive as well as negatives for the region.
What is an Atmospheric River?
These are large narrow bands of the earth’s atmosphere that carry a large amount of moisture that originates from tropical regions and carries moisture towards the poles. We can simply call them as rivers in the sky. These “rivers in the sky” of intense atmospheric moisture are invisible to the naked eye but can be visualised by scientists using satellite instruments with infrared sensors. The Earth’s atmosphere has four to five atmospheric at any given time and each river contains water equivalent to the basin of the Amazon river. Upon reaching the land, these rivers release this moisture, causing heavy rainfall and snow.
The river that is causing rains in California is called the Pineapple Express which originates in the subtropical waters around Hawaii.
Positive Impact and Associated Concerns
California was witnessing a dry spell for almost a decade but has received its fair share of rains this year. In 2022, California received rains caused by a barrage of atmospheric rivers that landed in the state. Usually, the Western states receive rainfall from October to December.
According to reports, the rains are ravaging the southern part of California, which does not have the storage capacity to capture the storm water.
The rains will prove to be a boon for the aquatic life and vegetation that have been facing an acute shortage of water for almost a decade.
Although the surplus water is good for the ecosystem and wildfire resistance, but the heavy rains will also promote the growth of shrubs and grasses that can become fuel for future fires during dry season. Additionally, the risk of landslides has also increased due to the soil being heavily soaked.
Climate Change to blame?
Anthropogenic greenhouse gas emissions have caused Climate Change, which has led to a considerable rise in the temperature of the atmosphere. Due to this increase in temperature, the atmosphere can now hold more moisture, as per the well-known Clausius-Clapeyron relationship. Therefore, even if the extratropical cyclones remain unchanged in their intensity or pattern, the increased moisture in the atmosphere will cause more intense atmospheric rivers and extreme precipitation. In recent years, we have observed a rise in the frequency and intensity of atmospheric rivers, along with an increase in extreme precipitation events.
Extreme precipitation can be beneficial for agriculture and water resources. However, it can also cause floods, mudslides, and surface runoff posing risks to people’s lives and property. This is a concern as the climate warms due to human activities. To effectively counter and prevent loss of lives due to these events, early warning systems are needed to give timely information on weather-related hazards. Communities can invest in flood control measures and upgrade infrastructure to withstand extreme weather. Education and outreach programs can raise awareness about the risks of extreme weather events. Ultimately, reducing greenhouse gases in the atmosphere by reducing fossil fuel burning and reaching net-zero emission goals is the solution.
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