Colour-coded alerts: U.P. establishes heatwave threshold for all 75 dists
SDMA conducted a comprehensive study in which experts analysed temperature patterns since 1982, spanning 42 years, to develop a three-tier heatwave alert system: yellow, orange and red.
Uttar Pradesh has become the first Indian state to establish specific heatwave thresholds for each of its 75 districts.
The State Disaster Management Authority (SDMA) conducted a comprehensive study in which experts analysed temperature patterns since 1982, spanning 42 years, to develop a three-tier heatwave alert system: yellow, orange and red.
The heat thresholds range from 36.7°C to 40.58°C for yellow alert, 39.09°C to 43.30°C for orange alerts, and 41.48°C to 45.34°C for red alert in Uttar Pradesh districts.
“It is essential to shape effective policies to safeguard public health, optimise agriculture, and urban planning,” said Lt General Yogendra Dimri, vice-chairman of SDMA.
Extreme heat events are linked to morbidity, mortality, and affect livelihood, agriculture, education, and day-to-day life in general.
The implementation of threshold-based warnings at the district level could be highly effective in preventing heat-related illnesses.
This new system allows district authorities to implement targeted measures or Standard Operating Procedures (SOPs), such as adjusting school timings and providing medical support, among other things, based on the local temperature conditions.
At the same time, it would decrease the dependence on the Indian Meteorological Department (IMD), which defines a heatwave as occurring when temperatures in a location exceed between 4.5 degrees Celsius and 6.4 degrees Celsius above the normal temperature or that exceeds 40 degrees in plains, 37 degrees in coastal areas and 30 degrees in the hills.
The heatwave threshold clearly defines the temperatures for each district at which three colour-coded alerts would be issued, said Dr Kashif Imdad, member of the state advisory committee of SDMA and one of the five experts who conducted the study.
While the team has established heat threshold for the entire country, Uttar Pradesh, has published the study and will implement the codes next year.
In order to determine the thresholds, the panel of experts developed a methodology incorporating the IMD’s concept of departure from normal in consultation with the World Meteorological Organisation (WMO) and World Health Organisation (WHO) for percentile-based thresholds. The experts established that the 50th percentile of maximum temperature for each location represented the usual temperature.
After studying the maximum temperatures over the past 42 years, the panel utilised the 80th, 88th, and 95th percentiles of maximum temperature to calculate yellow, orange, and red alerts for districts in Uttar Pradesh.
People’s vulnerability to heatwaves is relative and varies according to the usual temperature of their location,” said Imdad. “Mortality in Europe begins at 27 degrees Celsius because people are not adapted to high temperatures,” he said.
In Uttar Pradesh, people in districts close to the Himalayas experience lower temperatures compared to those in central, eastern, and Bundelkhand regions.
“The threshold cannot be the same for all districts, for example, 40 degrees Celsius for plains as per IMD,” he added.
The determination of thresholds helps in developing an evidence-based heatwave early warning system, unique to each district. The District Disaster Management Authority can declare heatwaves based on these threshold temperatures, which can be measured locally.
For instance, Bundelkhand districts have been found with exceptionally high temperatures, warranting a red alert from the outset. Banda, Jalaun, and Mahoba top the list with the highest orange temperatures. Similarly, Prayagraj, Kanpur, Hamirpur, and Kaushambi regions impact daily life and agricultural activities, as highlighted by the study, which also emphasises the widespread heat vulnerability in the region.
WHAT IS A HEATWAVE?
A phenomenon of prolonged periods of excessively high temperatures that affect communities.
Those who played a key role in the study include Dr Kashif Imdad, advisor, UPSDMA, Lucknow, Dr Mehebub Sahana, Dr Aarti Krishnan and Dr Upasak Das (all three of the University of Manchester, United Kingdom) and Dr Bhanu Mall, advisor, UPSDMA, Lucknow.
Specific temperature metrics used to declare the occurrence of a heatwave.
Temperatures vary from region to region, and current standards such as 40°C for plains may not be universally applicable due to regional temperature differences.
Heat thresholds enable districts to develop their own heatwave early warning systems. The District Disaster Management Authority can declare heat waves based on these thresholds, ensuring timely activation of heat wave SOPs or action plans without delays in declaration.