Major Scare Averted! Sudden “Flash Fog” Blankets Delhi-NCR, City Left Shrouded in Smoke-like Mist

Delhi experienced an unusually sharp cold on Wednesday morning, when a sudden blanket of dense fog engulfed the city, reducing visibility to nearly zero in a matter of minutes.

According to reports, around 7:45 to 8:00 AM, Delhi-NCR was hit by an abrupt and thick fog that startled commuters and residents alike. The phenomenon, identified by meteorologists as “flash fog” or “rapid-onset fog,” forms and dissipates very quickly, unlike conventional overnight fogs.

What Causes Flash Fog?

Weather experts explain that flash fog is the result of a combination of cold air patterns, high humidity, and a sudden drop in temperature. Delhi’s air was already saturated with moisture overnight. When a sudden chill swept in with light morning winds, the ground temperature dropped instantly, causing the air to reach its dew point. This led to immediate condensation and the rapid formation of water droplets in the air.

Pollution particles present in large cities like Delhi-NCR further facilitate the formation of these droplets by providing additional surfaces for condensation. Because of this, visibility can fall to just a few meters within minutes.

Another contributing factor was the relative stillness of the air. With minimal wind, the fog could not disperse, leading to its rapid accumulation over highways, residential areas, and parks. As the morning sun rose and temperatures warmed slightly, the delicate balance broke, and the fog quickly evaporated, vanishing as suddenly as it appeared.

Flash fog poses significant risks because it appears without warning, creating dangerous conditions for drivers and pilots alike. Unlike persistent overnight fog, there is little time to issue alerts or advisories.

Falling Temperatures Signal a Deepening Cold Spell

Delhi’s Safdarjung Observatory recorded a minimum temperature of 3.8°C, 3.6°C below normal. Palam recorded 4.4°C, Lodhi Road 3.6°C, Ridge 4.6°C, and I.A. Nagar 4°C. Temperatures 4.5°C to 6.4°C below normal trigger a cold wave alert. Maximum temperatures during the day are expected to reach around 20°C.

With winter intensifying, meteorologists warn that sudden flash fog events may recur, short-lived yet intense, just like the unexpected event witnessed today.