Hurricane Hillary

Hurricane Hillary

Subject :Geography

Section: Physical Geography

Context: Hurricane Hilary is set to become the first tropical storm to hit Southern California in more than 80 years.

More about the news:

• Hurricane Hilary is on the verge of making an extraordinary mark as the first tropical storm to make landfall in Southern California in over eight decades.
•  The National Weather Service (NWS) reports a historical trend wherein approximately five hurricanes typically hit the US coastline within a span of three years, but none have ventured towards the western coast.
• Consequently, the impending arrival of Hurricane Hilary, rapidly approaching Southern California and Mexico, stands as a highly uncommon and notable occurrence.
• As per latest estimates, the hurricane will make landfall in the Baja peninsula in Mexico, roughly 330 km south of the port of Ensenada.

What is Hurricane:

• A hurricane is a powerful and destructive tropical storm characterized by strong winds, heavy rainfall, and low atmospheric pressure.
• Hurricanes are also known as cyclones or typhoons in different parts of the world.In the Atlantic Ocean and eastern North Pacific, they are called hurricanes, while in the northwestern Pacific, they are referred to as typhoons, and in the South Pacific and Indian Ocean, they are known as cyclones.

Key characteristics of hurricanes:

• Low Pressure Center
  • Hurricanes have a well-defined centre of low atmospheric pressure, known as the eye.
  • The eye is typically calm and clear, with light winds, surrounded by a ring of intense thunderstorms called the eyewall.
• Strong Winds
  • Hurricanes are known for their powerful winds that can reach sustained speeds of at least 74 miles per hour or higher.
• Heavy Rainfall
  • Hurricanes produce heavy rainfall, which can lead to flooding, landslides, and storm surges
• Formation
  • Hurricanes form over warm ocean waters when the sea surface temperature is typically above 26 degrees Celsius.
  • Warm, moist air rises from the ocean’s surface, creating an area of low pressure.
  • As the air cools and condenses, it releases heat, which fuels the storm’s development.
• Categories
  • Hurricanes are categorized on the Saffir-Simpson Hurricane Wind Scale based on their maximum sustained wind speeds.
  • The scale ranges from Category 1 (weakest) to Category 5 (strongest), with each category representing a higher wind speed and potential for damage.

Why Hurricane Hillary is so rare:

• Nature of the ocean:
  • The Pacific coast rarely experiences tropical storms or hurricanes due to the characteristics of the ocean.
  • For hurricanes to form, ocean waters must be above 26 degrees Celsius (78.8 degrees Fahrenheit).
  • Ocean temperatures below this threshold hinder hurricane formation or cause rapid weakening when storms pass over cooler waters.
  • While warm temperatures prevail during hurricane season along the US east coast, the Pacific’s west coast remains significantly colder.
  • The Atlantic’s warm equatorial waters are transported northward along the US coast via the Gulf Stream.
  • Conversely, the Pacific’s cold current brings cooler waters from higher latitudes towards equatorial regions, making hurricanes less likely.
• Vertical wind shear:
  • Vertical wind shear refers to changes in wind speed with altitude in the Earth’s atmosphere, particularly in the upper levels.
  • This plays a critical role in hurricane formation, as hurricanes can extend up to 16 km into the atmosphere.
  • Strong upper-level winds inhibit hurricane formation by disrupting the storm’s structure, displacing warm temperatures above the eye, and limiting vertical ascent of air parcels.
  • Eastern Pacific winds tend to have stronger wind shear compared to the Gulf of Mexico, leading to fewer hurricanes along the western coast.
• Influence of wind steering patterns:
  • Trade winds are significant in directing hurricanes towards the US east coast, while deflecting them away from the west coast.
  • Hurricanes originating in the eastern Pacific, often near central Mexico’s coastline, typically follow a west-northwest trajectory that takes them away from the coast.