Ever wonder how much a cloud weighs? What about a hurricane? A meteorologist has done some estimates and the results might surprise you.

Let's start with a very simple white puffy cloud - a cumulus cloud. How much does the water in a cumulus cloud weigh? Peggy LeMone, senior scientist at the National Center for Atmospheric¹ Research in Boulder², Colorado, did the numbers.

"The water in the little cloud weighs about 550 tons," she calculates. "Or if you want to convert it to something that might be a little more meaningful … think of elephants."

Assume an elephant weighs about six tons, she says, that would mean that water inside a typical cumulous cloud would weigh about one hundred elephants.

The thought of a hundred elephants-worth of water suspended in the sky begs another question - what keeps it up there?

"First of all, the water isn't in elephant sized particles, it's in tiny tiny tiny particles," explains LeMone.

And those particles float on the warmer air that's rising below. But still, the concept of so much water floating in the sky was surprising even to a meteorologist like LeMone.

"I had no idea how much a cloud would weigh, actually, when I started the calculations," she says.

So how many elephant units of water are inside a big storm cloud … 10 times bigger all the way around than the "puffy" cumulus cloud? Again, LeMone did the numbers: About 200,000 elephants.

Now, ratchet up the calculations for a hurricane about the size of Missouri and the figures get really massive.

"What we're doing is weighing the water in one cubic meter theoretically pulled from a cloud and then multiplying by the number of meters in a whole hurricane," she explains.

The result? Forty million elephants. That means the water in one hurricane weighs more than all the elephants on the planet. Perhaps even more than all the elephants that have ever lived on the planet. 

　　想知道一朵云有多重吗？还有飓风？一位气象学家做了大概的估算，结果可能会让你大吃一惊哦。

　　让我们先从一团很普通的蓬松的白色积雨云算起。一朵积雨云所含的水有多重呢？科罗拉多州玻尔得国家大气研究中心的资深科学家佩吉·莱蒙算出了一组数据。

　　她推算：“一小片云大约含有550吨水。如果你想把它转换成更加实际一点的东西，那就想想大象吧。”

　　她说，假设一头大象有6吨重，那么一朵普通的积雨云所含的水就相当于大约100头大象那么重。

　　一想到100头大象那么重的水悬在空中，你不得不考虑另一个问题——是什么让它牢牢的挂在天空中的呢?

　　“首先，构成水的粒子并没有大象那么大，而是非常非常地小。”莱蒙解释说。

　　而且那些微粒漂浮在正在上升的暖空气上面。但是尽管如此，想到有这么多水漂浮在空中，哪怕像莱蒙这样的气象学家也会觉得不可思议的。

　　“当我刚开始计算的时候，我真的不知道一朵云有多重。”她说。

　　那么一块儿比“蓬松的”积雨云大10倍的暴风云中含有的水相当于多少只大象呢？莱蒙再次得出数据：大约是20万只。

　　现在，逐步计算像密苏里飓风那样的热带风暴的含水量，数据真是大的惊人。

　　“我们正在做的是从理论上测量一立方米的云所含的水的重量，然后再乘以整个飓风的体积。”她解释说。

　　知道结果吗?相当于4千万头大象。这就意味着飓风中所含的水比地球上所有的大象加到一起还要重，也许会超过地球上曾经有过的所有大象体重的总和。