What is Rapid Intensification of Hurricanes?
- Rapid Intensification is defined as increase in the maximum sustained winds of a tropical cyclone of at least 30 knots (about 35 mph) in a 24-hour period.
- Researchers have found that the likelihood of a hurricane undergoing Rapid Intensification has increased to 5% from 1% since the 1980s.
- It is especially problematic when it happens just prior to landfall as it gives residents less time to prepare.
Reasons for the Rapid Intensification of Hurricanes
- Role of Climate Change:
- More than 90% of the excess heat from human-caused global warming over the past 50 years has been absorbed by the oceans.
- These warm ocean waters provide fuel for hurricanes, which rely on a moist and unstable atmosphere. Warmer oceans mean there is higher rainfall during storms.
- Also, higher surface temperatures allow hurricanes to reach higher levels of maximum sustained wind.
- Role of vertical wind shear:
- Vertical wind shear is defined as change of horizontal wind direction and/or speed with height.
- According to a 2019 study, researchers found that warming temperatures may lead to weakening vertical wind shear, allowing hurricanes approaching the East Coast of the United States to intensify more rapidly. However, the study’s findings were localized.
How else Climate Change is Impacting the Hurricanes?
- Slower movement: Changes in the atmosphere induced by Climate Change are making Hurricanes move more slowly than they previously did.
- It leads to higher total rainfall and longer periods of high winds and storm surge in the coastal regions, resulting in more destruction.
- Poleward shift: The warming of mid-latitudes is leading to more storms occurring at higher latitudes.
- This northward shift has been observed in the Pacific, but not in the north Atlantic.
- This trend is worrying for mid-latitude cities such as New York, Boston, Beijing, and Tokyo, where “infrastructure is not prepared” for such storms.
- Temporal shift: Hurricane activity is common for North America from June through November, peaking in September. However, in the recent times, hurricanes have been forming earlier than usual.
- The same trend appears to be playing out across the world in Asia’s Bay of Bengal, where cyclones since 2013 have been forming earlier than usual – in April and May – ahead of the summer monsoon.
What are Hurricanes?
- Hurricanes, known generically as tropical cyclones, are low-pressure systems with organized thunderstorm activity that form over tropical or subtropical waters.
- Tropical storms are called by different names in the different regions of the world as shown in the diagram.
- Specifically, storms that form over the Atlantic Ocean or central and eastern North Pacific are called “hurricanes”
- Required conditions for hurricane development:
- Wind direction: The direction of circulation is different depending on where the storm is located: it is counter-clockwise in the Northern hemisphere and clockwise in the Southern hemisphere.
More on the News
- The National Hurricane Center had predicted the Hurricane Ian would rapidly intensify from a tropical storm to at least a category 4 hurricane in less than 72 hours.
- Also, the recent Super Typhoon Noru in Philippines experienced an intensification from the equivalent of a category 1 hurricane to a category 5 in less than 24 hours.