Residents felt the chill on Tuesday, as the minimum temperature dropped below that of Dehradun, Dharamsala and Nainital.
The Safdarjung observatory, Delhi’s primary weather station, logged a minimum temperature of 5.6 degrees Celsius while the minimum temperature in Dehradun was recorded at 7 degrees Celsius, Dharamsala at 6.2 degrees Celsius and Nainital at 7.2 degrees Celsius.
“A western disturbance led to a fresh spell of snowfall in the mountains resulted in cold northwesterly winds were sweeping through the plains,” an official said.
According to the India Meteorological Department (IMD), ‘very dense’ fog is when visibility is between 0 and 50 metres, 51 and 200 metres is ‘dense’, 201 and 500 ‘moderate’, and 501 and 1,000 ‘shallow’.
Western disturbances are storms that originate in the Caspian or Mediterranean Sea, and bring non-monsoonal rainfall to northwest India, according to the India Meteorologic
IMPACT OF WESTERN DISTURBANCES
There are several studies conducted by various scientific institutes in the country in regard to the impact of western disturbances during winter season on Indian climate. The studies show that;
- 30% of annual precipitation over North West Indian region (J & K, Ladakh, Himachal Pradesh &Uttarakhand) is received during winter and it is mostly associated with Western Disturbances. It also causes rainfall over the adjoining places of north India.
- Precipitation associated with Western Disturbances (WDs) influences Himalayan climate, glaciers, snow-water storage, flora, fauna, agricultural crops and human inhabitants etc.
The adverse weather elements associated with Western Disturbances are;
- Intense precipitation in the form of snow, rain or hail leading to landslides, avalanches and damage of agriculture and manmade structures.
- Dense to very dense fog events leading to interruption in aviation / rail / road transport services.
- Cold Wave to Severe Cold Wave and Cold Day to Severe Cold Day conditions after the passage of western disturbances.
However, precipitation from the western disturbances is very vital for the Rabi Crop over northwest India. Also snowfall/snowmelt in the Hilly regions contribute to river flow and drinking water for people living downstream.