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A mature thunderstorm cloud contains about 2 million tons of water, while the…

2026-08-08 · 05:38 UTC ·@aakashgupta ·1 min read

Brief

A mature thunderstorm cloud holds about 2 million tons of water, outweighing the 365,000-ton Empire State Building roughly fivefold as it drifts over Manhattan. Using a ~10 km × ~10 km storm cell with ~2 g/m³ of water yields that mass; 20 µm droplets and updrafts (over 100 mph) keep the water aloft until collisions produce rain. The photo was taken from the Empire State Building's 102nd floor, a structure struck ~25 times/year and once 8 times in 24 minutes.

Why it matters

A mature thunderstorm cloud contains about 2 million tons of water, while the Empire State Building weighs 365,000 tons — the storm above Manhattan outweighs the building roughly fivefold, hanging over about 1.6 million people.

Key details

  • The author's back-of-envelope uses a storm cell ~10 km wide and ~10 km tall with ~2 grams of water per cubic meter to reach the 2 million-ton figure.
  • Cloud water exists as ~20 µm droplets so air resistance and storm updrafts (which can exceed 100 mph) keep them aloft; rain forms only when droplets collide and grow. Photo taken from the 102nd floor of the Empire State Building, which averages ~25 lightning strikes/year and was once hit 8 times in 24 minutes; its antenna is a deliberate lightning rod.
Source evidence

A mature thunderstorm cloud holds about 2 million tons of water. The Empire State Building weighs 365,000 tons. When a storm rolls over Manhattan, the heaviest object in the sky outweighs the tallest building under it five times over. And the heavy one floats.

The math is simple enough to redo yourself. A big storm cell runs roughly 10 km wide and 10 km tall, carrying about 2 grams of water per cubic meter. Multiply it out and you get 2 million tons hanging overhead.

It stays up because the water exists as droplets around 20 microns across, so small that air resistance beats gravity. Each droplet falls slower than the storm's updraft rises, and thunderstorm updrafts can exceed 100 mph. The cloud is 2 million tons of water losing a tug-of-war with wind, in real time, over 1.6 million people.

Rain only happens when droplets collide, merge, and finally grow heavy enough to win.

One more layer. This shot came from the 102nd floor of the Empire State Building, which takes about 25 lightning strikes a year. It once got hit 8 times in 24 minutes. The antenna was designed as a lightning rod on purpose, to protect the blocks around it. The photographer went up during a thunderstorm and stood inside the most reliably struck structure in America to get the frame.

Gary Hershorn (@GaryHershorn)

A thunderstorm passes over lower Manhattan and One World Trade Center in New York, seen from the 102nd floor of the Empire State Building, Friday evening #newyorkcity #nyc #newyork @empirestatebldg #thunderstorm

— https://nitter.net/GaryHershorn/status/2085851584597021135#m