Nuking a Hurricane

Question: Why not use nuclear weapons to destroy hurricanes while they’re still far out at sea?

Several readers have asked that question. In the past, I’ve politely responded to those queries with a link to NOAA’s FAQ page for the official answer. However, now that we have high-ranking government officials asking that same question I think it’s time to address it.

The main graphic shows Hurricane Florence bearing down on Florida in August 2018. The visible circulation extends to 650 km (400 miles) in diameter. The width of the Florida peninsula is 80–150 km (50–100 miles). At the low angle of this satellite photo, perspective distorts their relative sizes.

For the proposed nuclear explosion I used a mushroom cloud approximately scaled to the size of the Tsar Bomba explosion. That cloud was 65 km (40 miles) tall and extended a comparable distance horizontally. It was visible from a distance of 1000 km (620 miles). The shock wave circled the Earth three times before dying out. The main graphic shows this detonation superimposed on the eye of the storm.

Tsar Bomba looks pretty impressive on paper. It literally fills the eye of the hurricane. You’d think a blast that size would at least make a “dent” in the storm. Ironically, it could actually add energy to the storm, increasing its intensity and wind speeds. To understand why, we need to look at how a hurricane forms and what keeps it going.

The graphic above shows the internal structure of a hurricane. Vectors indicate how multiple components interact to fuel these large rotating systems. Here’s what it takes to start them spinning:

  • The usual trigger is a tropical wave. Hurricanes in the Atlantic often start as a storm system that moves off the west coast of Africa. If it encounters the next five conditions, its circulation will be amplified and it will evolve into a tropical storm that can later become a hurricane.
  • The storm must form at more than 5° latitude from the equator. To start the spin of the storm, there must be a strong enough Coriolis force, and this force is at its minimum on the equator.
  • Ocean waters must be warmer than 26 °C (79 °F). At that temperature, evaporation of seawater is sufficient to fuel a storm. Evaporated water rises as a warm vapor, forming an updraft that draws in surrounding surface air. Ultimately, warm waters are the storm’s energy source.
  • Relative humidity levels from the surface upward to the cloud deck must be high. Otherwise, rising humid air would condense too soon and disrupt the convective dynamics.
  • Temperatures in the eye must remain cool enough for rapid condensation of rising water vapor. When the vapor condenses to a liquid it releases latent heat. This further warms the air and accelerates the updraft.
  • The layer of atmosphere above the hurricane, and below 12 km altitude (40,000 ft), must have minimal wind shear (a change in wind speed or direction with altitude). Wind shear can disrupt the storm’s structure by dissipating the warm air at the top of the eyewall, removing energy from the system. It can also reduce the amount of cool air descending into the eye, slowing the condensation of rising water vapor.

And now we can understand why “nuking a hurricane” is a really, really bad idea:

  • It wouldn’t work. In fact, it would very likely exacerbate conditions. The flash of the blast would cause additional water to evaporate from the ocean below. It might temporarily disrupt the downdraft of cool air feeding the eye, but when the mushroom clouds breaks through the upper atmosphere the downdraft would resume with a renewed vengeance. The horizontal shock wave from the blast would momentarily raise pressure in the eye, then propagate outward through the storm. That would be followed by a returning shock wave as displaced air rushes back into the eye. None of this would interfere much with the circulation feeding the eye, as the shock wave forces would be perpendicular to that circulation.
  • Detonating the blast inside the rain band (instead of the eye) would instantly vaporize any liquid water in those clouds. But the affected region would be only a few percent of the total rain band area. Although that would disrupt the circulation in that limited region, the inertia of the remaining circulation would quickly “erase the hole”.
  • Let’s put things into scale here. If you followed that link to NOAA you saw that an “average” hurricane releases energy at the rate of one 10-megaton nuclear weapon every 20 minutes. We just don’t have anything that can compete with that amount of power.
  • Also, lest it be forgotten, nuclear weapons release huge amounts of radioactive fallout that could be swept inland by the storm system. An entire coast could become the next Chernobyl. And of course, marine ecosystems would also suffer pollution from the fallout.
  • And finally, perhaps the most damning, IF the blast could somehow dissipate the concentrated energy of a hurricane, the First Law of Thermodynamics says that energy (and that of the blast) must go somewhere. Energy cannot be “destroyed”. It can at best be dispersed throughout the environment as lower temperature energy. Problem is, that’s what we’ve been doing with fossil fuels for the last 200 years. And as we’ve learned, adding heat to the environment exacerbates violent weather events. Stopping one hurricane might well cause the next to arrive even sooner.

So is there anything we could do to stop a hurricane?

The US government funded an attempt from 1962 to 1983. Dubbed STORMFURY, the experiment involved seeding the rain bands with silver iodide to cause premature condensation and interfere with eye formation. That experiment produced no statistically significant results, used up tons of expensive silver iodide, and was widely considered a failure.

Some scientists have suggested floating a layer of biodegradable liquid polymer on the ocean surface. This would inhibit the evaporation of seawater that fuels hurricanes, but the area of ocean needed to be covered makes that impractical. Others have suggested pumping cold water from the deep ocean to mix with the warm surface water. That would reduce evaporation, but would also wreak havoc with marine ecosystems by redistributing nutrients. And whatever the “fix”, we always come back to the First Law of Thermodynamics.

Given current technology there’s really no way to stop a hurricane, much less eliminate them. The best we can do is stop burning fossil fuels. Even then, in a healthy climate, hurricanes will still happen — but when they do, they’ll be less frequent and less severe.

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