severe rainfall alert / extreme rainfall alert

India, with its vast and diverse geography, is particularly susceptible to severe rainfall events, especially during the monsoon season. The India Meteorological Department (IMD) plays a crucial role in forecasting and issuing severe rainfall alerts to mitigate their impact.

IMD's Warning System: Color-Coded Alerts

The IMD employs a four-tiered color-coded warning system to communicate the severity of weather conditions, including severe rainfall:

Green Alert (All is well): No warning; no adverse impact is expected.

Yellow Alert (Be Aware): Indicates moderate to heavy rainfall that could disrupt daily life, but the risk is manageable. It suggests being updated on the weather situation.

Orange Alert (Be Prepared): Signifies heavy to very heavy rainfall, with potential for significant disruption and damage. This level calls for preparedness, as there's a higher likelihood of waterlogging, traffic issues, and localized flooding.

Red Alert (Take Action): This is the highest level of warning, indicating very heavy to extremely heavy rainfall(often exceeding 204.5 mm in 24 hours). A Red Alert means that immediate and extensive action is required by both authorities and the public to minimize risk and ensure safety. It implies a high probability of severe impacts such as widespread flooding, landslides, significant disruption to transportation and power, and potential loss of life.

Criteria for Red Alert Rainfall

While the exact thresholds can vary slightly based on regional vulnerability and typical rainfall patterns, a Red Alert for rainfall typically indicates:

Extremely Heavy Rainfall: Usually defined as rainfall exceeding 204.5 mm (approximately 8 inches) in a 24-hour period.

Very Heavy Rainfall: Could also trigger a red alert if sustained over a shorter period (e.g., 50 mm in an hour in urban areas) or if combined with other factors like a high tide (in coastal cities), saturated ground, or a strong weather system.

Impacts of Severe Rainfall Alerts in India

When a Red Alert is issued for severe rainfall in India, the impacts are often widespread and challenging:

Widespread Flooding and Waterlogging: Low-lying areas, urban centers, and even major roads and railway tracks become submerged. This leads to immense disruption, as seen recently in cities like Mumbai, Thane, and Hyderabad.

Disruption to Transport:

Local Trains: Mumbai's lifeline, local train services, are frequently delayed, suspended, or even cancelled due to waterlogged tracks and signal failures, crippling commuter movement.

Road Transport: Roads become impassable, leading to severe traffic congestion and diversions. Vehicles can get stranded in deep water.

Air Travel: Reduced visibility and waterlogging at airports can cause significant flight delays, diversions, and cancellations.

Landslides and Mudslides: Hilly regions, especially the Western Ghats, the Himalayas, and the Konkan coast, are highly vulnerable. Saturated soil can lead to dangerous landslides, blocking roads and endangering lives.

Infrastructure Damage: Homes, businesses, and public infrastructure suffer damage from water ingress, collapsing walls, and tree falls. Power outages are common due to damaged lines or as a precautionary measure.

Agricultural Losses: Farmlands are often submerged, leading to significant crop damage and affecting the livelihoods of farmers.

Loss of Life and Injuries: Direct impacts include drownings, electrocutions, building collapses, and accidents due to hazardous conditions. Rescue operations become critical.

Evacuations: Residents in low-lying or vulnerable areas, particularly near swelling rivers (like the Mithi River in Mumbai or the Yamuna in Delhi), may need to be evacuated to temporary shelters.

Closure of Institutions: Schools and colleges are frequently declared shut to ensure the safety of students and staff and to ease traffic congestion. Government and private offices may advise or mandate work-from-home.

Recent Examples (as of August 2025)

The monsoon of 2025 has seen multiple instances of severe rainfall alerts and their consequent impacts across India:

Mumbai and Maharashtra: Mumbai, Thane, Palghar, Raigad, Ratnagiri, and Pune's Ghat areas have been under "Red Alert" multiple times in August 2025. This has resulted in:

Over 300 mm of rainfall in 24 hours in parts of Mumbai.

Closure of schools and colleges in affected districts.

Significant disruption to local train services and prolonged waterlogging in areas like Sion, Kurla, and Andheri Subway.

Flight delays and diversions at Mumbai Airport.

Evacuation of hundreds of residents from low-lying areas, such as Krantinagar in Kurla, as the Mithi River swelled.

Fatalities due to rain and flood-related incidents (e.g., electrocution, wall collapses).

Deployment of NDRF and SDRF teams for rescue and relief operations.

Telangana: Districts like Mulugu, Bhadradri Kothagudem, and Mahabubabad received "very heavy to extremely heavy rainfall," leading to

inundation of thousands of acres of crops.

Damage to roads and culverts, cutting off connectivity to villages.

Overflowing streams and canals.

Delhi-NCR: While less frequent, Delhi also experienced "Red Alerts" this monsoon, causing:

Severe waterlogging and traffic chaos across Delhi, Noida, Gurgaon, and Faridabad.

Disruptions to over 300 flights at Delhi airport during intense spells.

Concerns about the Yamuna River crossing the danger mark, prompting alerts for areas along its banks.

Preparedness and Response

The IMD's severe rainfall alerts serve as crucial calls to action. Authorities activate disaster response units, monitor water levels in dams and rivers, and advise citizens. For the public, it reinforces the need to:

Stay updated with official weather reports.

Avoid unnecessary travel, especially to waterlogged or flood-prone areas.

Secure homes and move valuables to higher ground.

Prepare emergency kits.

Follow advisories from local municipal corporations and disaster management agencies.

These alerts are vital for India's resilience against the increasing intensity of monsoon events, allowing for timely responses to protect lives and property.