# Cyclone Phailin Will Do Major Damage

Cyclone Phailin struck the east coast of India Saturday evening (India is 12½ hours ahead of PDT). A few hours before landfall top winds were estimated at 120 knots, gusting to 145 knots (around 135 mph, gusting to 165 mph).

It will be a while before we know the true extent of the damage. It’s likely catastrophic.

A cyclone is the name used near the Indian Ocean for storms we call hurricanes. In the Western Pacific these same storms are called typhoons.

Storms like this kill in a multitude of ways. Here in the US the biggest threat is not the wind!

“In the last 30 years, inland flooding has been responsible for more than half the deaths associated with tropical cyclones in the United States.”
Ed Rappaport
National Hurricane Center

That’s likely the case in India as well.

The Indian coast on the Bay of Bengal is reasonably flat with small mountains as close as 15 miles from the shore. Tidal and inland flooding are likely. Mudslides on rain soaked hillsides are possible too.

The force of the wind is so strong it’s difficult to fathom based on our own personal experiences. I’m going to use a little math, but I’ll explain every step. It’s worth understanding.

The force exerted by wind is logarithmic. That means in the calculation we multiple the wind speed by itself–we square it.

Simply put, if you double the wind speed, you quadruple the force! A 60 mph wind has four times the force as a 30 mph wind. A 120 mph wind has 16 times the force as that 30 mph wind!

Take a sheet of standard 4′x8′ plywood–32 square feet. If it was hit directly by a 165 mph gust it would be subject to over a ton of force–2,230 pounds!

The formula is: wind speed x wind speed x .00256 equals the force per square foot. Multiply by 32 for a sheet of plywood. So…

165 * 165 *.00256 * 32 = 2230.272 pounds

It will be a while before we really know what’s gone on in India. However, based on what we know expect a major tragedy even though this storm was well forecast and warnings issued. Sometimes there’s just no place to go.

### 2 Responses to “Cyclone Phailin Will Do Major Damage”

1. Diane K says:

That’s exactly the problem. Even with a head start I’m sure they couldn’t get far enough away. So many lives will be lost. Horrific. Very sad.

2. Bob says:

Exponential, not logarithmic. (Sorry. Engineers are nitpickers.)