Number Theory: Are there long-term changes happening in western disturbances?

One reason IMD scientists cited for low snowfall this winter was that strong western disturbances were not arriving over India.

By all accounts, the ongoing winter is exceptional in India. This season, which begins officially in December, started feeling winter-like only towards the end of December. Snowfall and winter rain in India’s hilly states was so late that they experienced record number of active fires this January. India’s snow pack this winter is also the lowest in satellite records. Despite these signs of a warm winter, the northern and north-western plains experienced daytime temperatures well below normal all January because of fog higher up in the atmosphere. Since the immediate reason behind all these trends is the lack of strong western disturbances over India, it is worth understanding them in more detail. Here are four charts that do that.

Homeless people sit around a bonfire on a cold winter morning under a National Highway flyover in Gurugram. (Parveen Kumar/HT Photo)