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India's vulnerability to flash floods and how to prepare for them

As unpredictable weather patterns continue, the Indian Meteorological Department has been issuing weather warnings, including flash floods in the northern regions of the country



BS Web Team New Delhi
In June alone, India has already witnessed two incidents of flash flooding in the country's northern region.

Two hundred tourists are currently stranded in the Bagipul region of Himachal Pradesh, less than two weeks after 3,000 tourists were stuck in Pegong, Sikkim, after a flash flood hit the region, blocking national highway 10.

As unpredictable weather patterns continue, impacting crop production, inflation rates and increasing the risk of natural disasters, here is a closer look at the phenomenon known as flash floods.

What are flash floods?
Flash floods are sudden and rapid flooding events that happen within a short period of time. According to the National Weather Service of the United States, these floodings typically occur within six hours of heavy rainfall or other intense water-related events.

They are characterised by swift and powerful flows of water that can quickly inundate low-lying areas, such as riverbeds, canyons, and urban areas with poor drainage systems.

What makes flash floods dangerous?
The defining feature of flash floods is their speed and unpredictability. They can occur without warning, catching people off guard and leaving little time for preparation and evacuation.

The rapid rise in water levels can reach several feet in just a few minutes, destroying property, and the force of the water can be powerful enough to uproot trees, carry away vehicles, and damage buildings.
Flash floods also pose a significant threat to life, along with property and infrastructure.

These floods are known to cause drowning, injuries, and fatalities, as well as destroy homes, roads, bridges, and other structures. The fast-moving water can also erode the ground, leading to landslides that further exacerbate the damage.

India's vulnerability to floods

According to the National Disaster Management Authority (NDMA), out of the country's total geographical area of 329 million hectares, more than 40 million hectares are flood-prone.

Floods are a recurrent phenomenon and result in significant loss of lives and damage to livelihood systems, property, infrastructure, and public utilities. Flood-related damage has been rising in the country, with data showing an average annual flood damage of Rs 4,745 crore between 1996-2005, compared to Rs 1,805 crore in the 53 years before that.

Each year, floods affect an average of 7.5 million hectares of land, resulting in the loss of 1,600 lives and causing damage amounting to Rs 1,805 crore to crops, houses, and public utilities, according to the NDMA's data.

The highest number of fatalities was reported in 1977 at 11,316.

What is the cause of the rising number of floods?
Factors such as population growth, rapid urbanisation, increased developmental and economic activities in flood plains, and the impacts of global warming contribute to the increasing flood damage.

Flash floods are often triggered by intense rainfall, but they can also result from other factors like dam or levee failures, rapid snowmelt, or sudden water releases from reservoirs. Cyclones, cyclonic circulations, and cloud bursts can also cause flash floods.

About 80 per cent of India's annual precipitation occurs during the monsoon months from June to September, leading to heavy rainfall and increased flood risks.

How to prepare for flash floods?
Early warning systems, such as weather forecasts and monitoring of river levels, are key to mitigating the risks associated with flash floods. The India Meteorological Department (IMD) issues warnings for regions that may be at risk for flash floods.

Public education on flood preparedness and evacuation procedures is also important to minimise the impact of flash floods.

Listening to the radio or TV for updates and information is crucial whenever there is excessive rainfall.

There may not be obvious warning signs for flash floods; therefore, the NDMA also instructs people to immediately move to higher ground without waiting for instructions if flooding seems likely.

Preparing for evacuation
The NDMA also has a list of what to include in an emergency kit for floods as well as guidelines to follow in the event of flooding. NDMA has prepared guidelines to assist implementing agencies and stakeholders in effectively addressing critical areas for mitigating flood damage.

The emergency kit should include battery operated torch, extra batteries, battery operated radio, a first aid kit and essential medicines, emergency food (dry items) and water (packed and sealed), candles and matches in a waterproof container, a knife, chlorine tablets or powdered water, important documents (such as ration card, voter id card, etc.), cash, Aadhaar card and ration card, thick ropes and cords, and a pair of shoes.

In case of evacuation, people must ensure their homes are secure; items are moved indoors and placed on upper floors to contain the damage. Furthermore, while switching electrical items is important, this should not be attempted if the individual or items are wet.

People should also avoid walking through moving water and use a stick to check for ground stability. Prioritising personal safety is essential during flood emergencies.

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First Published: Jun 26 2023 | 3:53 PM IST

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