Hole Punch Clouds are simply high clouds that look like somebody punched a hole in them. The name is not scientific and sometimes you hear it as Punch Hole Clouds but they look unusual. Hole punch clouds are generically called dissipation holes. When they stretch out in long lines, they are called dissipation trails. If you look you could probably see them fairly often when we have Altocumulus and Cirrus clouds but usually they are not too dramatic. On December 11, 2003 the sky was dramatic over Mobile County, Alabama. Washington County, Alabama later saw a similar event on January 29, 2007.
In the 2003 event, first a layer of Altocumulus clouds moved in from the west. Even though these clouds were made of water droplets they were actually supercooled water. In other words, the temperature of the water was below freezing. These clouds were just below airplane condensation trails (contrails) indicating that the humidity was high at that level of the atmosphere. Then close to noon, within minutes, the blanket of Altocumulus clouds developed a hole. The hole turned out to be crystals of ice, transformed into regular Cirrus clouds, and then falling. By definition this was precipitation and since Cirrus clouds are made of ice crystals, you could call it snow, fallstreaks, or Virga. It evaporated well before hitting the ground. All of this is common but what was uncommon was the perfect circular shaped that grew within a matter of minutes.
Depending on where you were, it may have been hard to tell that the clouds in the middle of the hole were falling lower than the other clouds. For this phenomenon to occur you only need to do one thing- increase the relative humidity fast. There are several ways to do this.
An easy way to artificially raise the humidity is to fly a jet plane through the cloud. As the engines burn fuel, they release water vapor to increase the relative humidity. Ice crystals that are already in the air will pull as much of the vapor as possible and then grow larger, and heavier, to fall. This is one of the reasons we see condensation trails behind jets that fly high. Jet engines also release tiny particles that serve as a base for ice crystals to form on.
Other ways that relative humidity is raised naturally is when waves in the atmosphere cause the air to rise and sink, just like water waves near a beach. Rising air cools and that can cause the relative humidity to rise and produce precipitation. Even if the air sinks, it’s possible that ice crystals may fall into a region of high moisture that is not frozen and immediately form big crystals.
The process is pretty simple but there are details. For example, It’s possible to have water droplets when the temperature is way below freezing. We called them supercooled. It’s also possible for the relative humidity to be over 100%. In weather, there’s an exception to every rule.
Beware the claim that something nefarious is occurring when you see hole punch clouds or dissipation trails or vapor trails, which some people call chemtrails. A “chemtrail” is a name erroneously given to contrails (water vapor condensation trails) that some people believe are trails of chemicals released from aircraft to harm or control people. There’s never been any credible confirmation that this is occurring or has ever occurred. There is also no scientific definition of a chemical trail. Note that water vapor, oxygen, and nitrogen are all chemicals. The theories promoted online and in social media simply repeat misinformation or opinion with little scientific basis, rather than peer-reviewed scientific research by people expert in aviation, chemistry or atmospheric science. For example, the statement, “contrails are short, chemtrails are long” has absolutely no science behind it. Assuming that harmful chemical trails even exist, that would be the same as saying, “people who wear glasses are smart, and people who don’t wear glasses are not”!
A condensation trail forms as a byproduct of combustion. Water vapor is released by aircraft engines and it condenses in the cold altitudes in which aircraft fly. This vapor forms lines (twin tubes in the vortex tubes created by airplane wings) of ice crystals that spread and become cirrus clouds. Condensation trails that occur for long periods in thin layers of Altostratus clouds can create channels known as “ice channels” or “ice canals.”
Contrails are very common in high-aircraft traffic routes, and they have greatly increased in the last several decades along with the large increase in airplane traffic. The number of planes in the air in the US has more than tripled since the 1960s. More contrails are seen because there have never been so many planes at high altitudes before. http://www.rita.dot.gov/bts/sites/rita.dot.gov.bts/files/publications/national_transportation_statistics/html/table_01_11.html
In the US alone, there are tens of thousands of daily commercial passenger flights daily. http://maps.unomaha.edu/animatedflightatlas/FlightTrafficAnimation.html You can track the flight number, airline, and altitude using any of several online flight trackers, and compare that to the humidity aloft to see the connection.
Not all flights are at the altitude to produce contrails. The length and persistence of a condensation trail is controlled by the humidity at flight level, which is not ordinarily related to the humidity at ground level. You can see profiles of temperature and humidity. http://www.spc.noaa.gov/exper/soundings/ These profiles give a pretty good idea of where vapor trails and high clouds are more likely. How a condensation trail changes shape is controlled by wind speed and direction at and around flight level, which is also independent of what happens at the ground. Contrails do what clouds do; they float and drift. They do not fall to the ground.
What “chemtrail” theories fail to do is explain why and how someone or some agency would do something that is so obvious to cause harm and impact every living creature on Earth, while occurring over every major seat of power in the world. No one has presented any authentic document or first-hand (whistle-blower) knowledge of chemical trails created to harm people. With no solid evidence, no media outlet can verify this theory. Anybody can create and post a document or video online that looks convincing but the logic of chemical trails comes up short, whereas the science of water vapor trails from combustion can be verified by simple experiment.
For more on the science check out these sources