What Happens When a Storm Passes
Over Land- Landfall
Definition of
Landfall
- Landfall
occurs when the eye of a tropical cyclone crosses from water onto
land.
- The eye is the calm center of the
storm with descending cold air, surrounded by the eyewall, which
has strong thunderstorms, rain, and powerful winds.
- Storm intensity
is usually higher around the eye, making landfall a critical and often
dangerous event for human settlements.
Impact of Landfall
1. Weakened
Cyclone:
o Cyclones
draw moisture from the sea, fueling their strength.
o On
land, the lack of a moisture source causes the storm to weaken.
o The
degree of weakening depends on factors such as:
§ Dryness
of the air over land.
§ Terrain
and other environmental conditions.
2. Severe
Weather Effects:
o Heavy
Rainfall: Flooding of coastal and inland areas is common.
o Strong
Winds: Damage to infrastructure, trees, and power lines.
o Storm
Surges: Coastal flooding caused by the storm pushing seawater
onto land.
o Compounded
Flooding: Storm surges prevent rainwater from draining inland
areas.
Cyclones Over Land
- Cyclones often weaken after landfall and
may dissipate completely. However, under certain conditions, they
may re-emerge:
- Example: Cyclone Gulab (2021):
- Made landfall in Andhra Pradesh.
- Weakened while crossing peninsular
India.
- Re-emerged in the Arabian Sea as Cyclone
Shaheen after four days.
Significance of
Understanding Landfall
- Disaster Preparedness:
- Predicting landfall helps authorities
plan evacuations and emergency responses.
- Coastal and low-lying areas are especially
vulnerable to storm surges and flooding.
- Climate Impact:
- The frequency and intensity of cyclones
are influenced by climate change, emphasizing the need for
resilient infrastructure and advanced forecasting.
Conclusion
Landfall marks a critical
phase in the life of a cyclone, transitioning from an ocean-fueled storm to a
weakening system over land. While the storm’s intensity diminishes
post-landfall, its immediate impacts—strong winds, heavy rain, and storm
surges—pose significant risks to coastal and inland communities. Understanding
the dynamics of landfall is crucial for mitigating damage and improving
disaster response strategies.
MCQs
1. What is the term
"landfall" in the context of tropical cyclones?
A. The moment when a cyclone
forms over the sea
B. The process of a cyclone dissipating over land
C. The moment when the eye of a cyclone crosses from water onto land
D. The point where storm surges subside completely
Answer: C.
The moment when the eye of a cyclone crosses from water onto land
2. Which of the following
factors contributes to the weakening of a tropical cyclone after landfall?
1. Loss
of moisture supply
2. Interaction
with dry air over land
3. Friction
with land surfaces
Options:
A. 1 only
B. 2 and 3 only
C. 1, 2, and 3
D. 1 and 3 only
Answer: C.
1, 2, and 3
3. What is a major danger
associated with cyclones making landfall?
A. Formation of new cyclones
in nearby regions
B. Increased ocean salinity near coastal areas
C. Storm surges that flood coastal areas and block inland drainage
D. Complete dissipation of cyclone energy leading to unpredictable weather
Answer: C.
Storm surges that flood coastal areas and block inland drainage
4. Which of the following
cyclones re-emerged after crossing peninsular India and formed a new storm in
the Arabian Sea?
A. Cyclone Phailin
B. Cyclone Amphan
C. Cyclone Gulab (as Cyclone Shaheen)
D. Cyclone Nisarga
Answer: C.
Cyclone Gulab (as Cyclone Shaheen)
5. What is the primary
function of the "eyewall" in a tropical cyclone?
A. It provides calm
conditions at the center of the storm.
B. It circulates cold air downward to cool the ocean.
C. It consists of high thunderstorms bringing rain, lightning, and strong
winds.
D. It stabilizes the cyclone by reducing wind speeds.
Answer: C.
It consists of high thunderstorms bringing rain, lightning, and strong winds.
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