What is cold wave?
Cold wave is characterized by a rapid and marked fall of temperature. The term ‘cold’ describes an unusual fall in temperature that is triggered by the transport of cold air masses into a specific area.
The “wave” in cold wave is apparent in the upper-air flow (the jet stream), which is usually amplified into a strong ridge-trough pattern during a major cold outbreak.
Cold waves affect much larger areas than blizzards, ice storms, and other winter hazards.
Formation of Cold Waves
The core requirement of a cold wave at the surface is a strong high pressure center that forms during winter in high latitudes.
Cold polar or Arctic air masses are relatively shallow, extending one to several kilometre above the surface.
What damage can arise?
• The cold wave can negatively impact the safety of aviation operations.
• Fatal accidents can occur if people fail to adapt their driving to road conditions.
• Ice rain can cause ice fractures in trees and telephone wires.
• Exposure to extreme and especially unexpected cold can lead to hypothermia and frostbite, which can cause death and injury.
Cold waves can be forecast by modern weather forecasting. The weather forecasts can disseminate useful warnings to prevent traffic accidents.
Contemporary examples of cold waves:
• February 2016 North American cold wave
• January 2016 East Asia cold wave
• February 2015 North American cold wave
• November 2014 North American cold wave
• Early 2014 North American cold wave
• January 2017 North India observed the cold wave.
Cold wave in context with India in 2017:
An active western disturbance is affecting Western Himalayan region and northern India, this disturbance affects the states like, J&K, Himachal Pradesh, Punjab, Haryana, West Uttar Pradesh, Delhi, Chandigarh and some part of north Rajasthan furthermore, a cold wave at a few places in Bihar, Madhya Pradesh, Vidarbha and interior Odisha has been observed.
Effects and weather conditions:
In Himachal Pradesh -Shimla received heavy rainfall, likewise, cold wave intensified in Dharmashala. Uttar Pradesh’s Moradabad received light rain showers, lucknow has records decades coldest days; in Uttarakhand the upper reaches of Nainital received snowfall. Srinagar- Jammu national highway was closed, virtually cutting of the vally from rest of the country.
Avalanche –prone areas of Baramulla, Kupwara, Bandipora, Kistawar, Rajauri, Doda, Poonch and Riyasi district of J&K goes on high alert and classified as ‘medium danger for peoples movement’