Two potential cyclonic storms are forming in the Bay of Bengal, with global forecast models indicating a possible Fujiwhara interaction between them.

Fujiwhara Effect

• A rare meteorological phenomenon where two nearby cyclonic systems begin to rotate around a common centre due to interaction of their wind circulations.
• Identified by Sakuhei Fujiwhara (1921), it occurs mostly in the tropical cyclone belt when storms are within ~1,400 km of each other.

Factors Aiding Its Occurrence:

• Proximity of two cyclones within a threshold distance (typically <1400 km in the Indian Ocean).
• Similar rotational direction (counter-clockwise in the Northern Hemisphere).
• Favourable sea surface temperatures >26°C supporting sustained convection.
• Low vertical wind shear allowing stable cyclone structure.

How it forms?

• Close Formation: Two cyclones forming within ~1400 km begin influencing each other’s wind fields and natural movement patterns due to proximity.
• Wind Interaction: Their outer rainbands and upper-level winds overlap, creating deformation zones that gradually pull the systems toward each other.
• Coupled Circulation: The interacting winds generate a shared pivot point, forcing both cyclones to rotate in curved, mutually influenced paths.
• Orbiting: If one storm is stronger, the weaker one revolves around it and may eventually be absorbed due to energy imbalance.
• Merger: When centres move very close, the vortices fuse into a single, larger cyclone with enhanced convection and stronger winds.
• Weakening: Competition for heat and moisture can deprive the weaker cyclone of inflow, triggering rapid weakening or dissipation.
• Deflection: If interaction is weak, storms may push each other onto diverging paths, adding significant uncertainty to forecasts.

Key features -

1. Mutual Rotation: Both cyclones circle a common centre anti-clockwise, altering their original trajectories and movement speed.
2. Energy Transfer: The stronger system can steal momentum or moisture from the weaker one, reshaping their relative strengths.
3. Track Uncertainty: Steering winds get disrupted, making prediction of landfall, intensity, and movement highly challenging for meteorological agencies.
4. Possible Fusion: Close approach may cause the cyclones to merge into a more intense system with higher rainfall and damaging winds.
5. Stalling: Storms may slow down or stall during interaction, prolonging rainfall events and increasing flood risks.

Implications:

1. Forecast Challenges: High uncertainty delays accurate warnings for landfall and complicates planning for evacuation and relief operations.
2. Heavy Rainfall: Prolonged interaction increases rainfall over TN, Andhra, Odisha, Bengal, Sri Lanka, and Myanmar, worsening flood potential.
3. Intensification Risk: Energy transfer or merger can rapidly strengthen one system, raising threats of severe winds, storm surge, and coastal damage.

Ethiopia’s Hayli Gubbi volcano

• A massive volcanic ash cloud from Ethiopia’s Hayli Gubbi volcano—which erupted after nearly 10,000 years—has drifted toward India, raising concerns over air quality and aviation.
• Hayli Gubbi is a shield volcano in Ethiopia’s Afar Region, known for broad, gently sloping volcanic structures formed by low-viscosity basaltic lava typical of the East African Rift system.

Located In: It lies in the Afar Depression of Ethiopia, at the southern end of the Erta Ale volcanic range, one of the most active tectonic and volcanic zones in the world.

History Background:

• No confirmed eruptions for ~10,000–12,000 years (Holocene).
• On 23 November 2025, a sudden sub-plinian eruption produced an ash plume reaching 45,000 ft (FL450).
• The plume drifted across Red Sea, Yemen, Oman, and then moved east toward western India.

Key Features:

• Shield volcano type—broad, low-gradient, large lava fields.
• Part of the divergent plate boundary where the African Plate is rifting.
• Eruption produced volcanic ash, SO₂, glass shards, and rock particles transported at high altitudes (15,000–45,000 ft).
• Classified as sub-plinian due to vertical column height and ash dispersal scale.

Other Major Volcanoes in Africa:

1. Mount Nyiragongo (DR Congo) – One of the world’s fastest lava flows.
2. Mount Silali (Kenya) – Extinct caldera volcano.
3. Dabbahu Volcano (Ethiopia) – Rift-related fissure eruptions.
4. Mount Alayta (Ethiopia) – Part of Afar Rift.
5. Ardoukoba (Djibouti) – Erupted in 1978.
6. Mallahle (Ethiopia) – Stratovolcano.
7. Asavyo (Ethiopia) – Volcanic field within Afar rift.

Impact on India:

• Air Quality: Ash is at high altitudes, limiting ground-level mixing; Delhi is unlikely to see major AQI deterioration.
• Skies may appear hazy/darker but pollutants will remain mostly aloft.
• Health & Climate: SO₂ can contribute to acid rain regionally, but concentrations over India appear limited.
• Volcanic particles may briefly affect solar radiation and visibility.