Weather Whys

By Robert Morales —

Q: How high can thunderstorm clouds be?

A: It's common for many cloud tops in a thunderstorm to be higher
than 55,000 feet above sea level, says Brent McRoberts of Texas A&M
University. Clouds over that range belong in a special category. “That
may be as high as they get over the U.S., but in other parts of the
world, thunderstorm clouds can be even higher,” he says.

“In 1990 in the Coral Sea off eastern Australia, some nearby weather
balloons measured a thunderstorm cloud to be at least 63,000 feet high.

And in the northern Australia and Indonesia area, sometimes called
the ‘maritime or oceanic continent'' some of the highest clouds known
have been reported, several measuring from 65,000 to 72,000 feet by
astronauts in the space shuttle. It can happen, but it's rare to see
thunderstorms reach more than 65,000 feet.”

Q: Does the height of a thunderstorm cloud affect how strong it
is?A: Yes, that is usually the case, McRoberts adds. Storm clouds that
exceed 50,000 feet are almost always stronger than ones that are at just
15,000 feet.

A: “The higher the cloud, the more energy and motion inside the cloud,
and that's why these produce such strong winds, hail and rain,” he says.

“This motion inside the thunderstorm is called an updraft. Water and
ice particles within the thunderstorm rise and fall inside the storm
until they become too heavy to be supported, which at that time they
fall out of the storm as hail.

Usually, the higher the thunderstorm, the better the chances are of
it producing large hail. When you see a big thundercloud in the sky with
a bright white top and the bottom of it is very dark, it is usually
producing a powerful storm.

When clouds reach 50,000 feet or higher, they even affect airplanes.
The normal cruising range for passenger jets is in the 30,000 to
40,000-foot range. Pilots try to fly around such large storms, and this
sometimes means they have to take detours of 100 to 200 miles or more.”