Can Hot Air Balloons Fly in the Rain?

You feel a few drops of water on your head, then a few more. Could it really be rain? You had checked the forecast yesterday and the day was supposed to be clear, but obviously, it’s not. Will you be able to go hot air ballooning today like you planned or will the rain ground you?

Hot air balloons will not fly in the rain primarily because rain weighs down the balloon and cools the envelope’s air, both of which make the balloon pilot have to use more propane. Rain also affects visibility and increases wind. Landing can be a risk as well if the ground is muddy.

In this article, we’ll discuss further the dangers of hot air ballooning on a rainy day. We’ll also talk about what would happen should a sudden storm emerge when you’re already up in the sky, so keep reading!

Why Hot Air Balloons Won’t Fly in the Rain

To many people, rain is calming. Listening to the sound of the rain pelting the balloon envelope while you sit warm and dry in the gondola might seem like just the relaxing excursion you need, but it shouldn’t happen. Per the intro, here are five great reasons a balloon pilot will not take off in even a light drizzle.

Weighs Down the Balloon

When you get caught in a storm and your clothes are wet, they’re heavier, right? The material is saturated in water, so it will weigh more until it can dry. Although balloon envelopes are made of fire-resistant ripstop nylon, the nylon isn’t waterproof or even water-resistant. As the water droplets accumulate on the envelope, the nylon absorbs them and gets heavier.

According to Amco Polymers, “moisture acts as a plasticizer in nylon and therefore reduces strength and stiffness properties but increases elongation and toughness. In general, as moisture content rises, significant increases occur in impact strength and other energy absorbing characteristics of the material.”

In other words, the envelope might be tougher when wet, but it’s admittedly weaker too. We don’t know about you, but when you’re flying at least 1,000 feet in the air, you don’t want to be in a vessel where any parts are described as weak.

Cools the Envelope Air

We’ve talked on this blog about cool air when ballooning, as the coldness allows for more buoyancy from your balloon. However, as we always say, the air within the balloon must be a consistently warm temperature for that to happen. It’s really hard to maintain the same temperature when the envelope is wet.

The envelope’s temperature will come down instead of remaining warm like it should. Now, instead of the balloon pilot using the burner system to provide lift to the balloon, they’re really trying to dry the envelope. However, this is a losing battle considering the rain is still ongoing.

If you’ve missed some of our other posts on hot air ballooning, allow us to quickly explain how balloons fly. The burner system sends heated, evaporated propane to the inside of the envelope to guide in its ascension. Once in the sky, the hot air can provide lift. To guide you to the ground for a landing, the balloon pilot stops using the burner system in short intervals, as the cool air will bring the balloon down.

The cooler, wetter, heavier balloon envelope is going to have a much harder time staying afloat than if the envelope is warm and dry. What results is the balloon pilot burns through more propane than usual to maintain altitude. On the part of the balloon company, it’s a much costlier endeavor to fly in the rain than it is in clearer conditions.

Might Increase Wind

If you’ve ever noticed that besides the darker conditions that can precede a rainstorm that the winds pick up as well, this isn’t a random coincidence. To understand why, you first have to know how rain happens.

The water droplets in a cloud can become condensed through atmospheric conditions, increasing droplet size. As the droplets form into a liquid, the transition causes the production of heat. Yet many rainstorms occur during a cold front, decreasing the temperature and air density. These air changes can be enough to generate wind.

In a thunderstorm, the air closer to the ground is humid, but the warm air begins to rise. The water vapor in the air cools down when it meets denser cold air and then becomes condensed into droplets. The droplets, in large enough numbers, will turn into raindrops. Due to the complexity of a storm’s wind patterns, it’s also not unusual for winds to whip up ahead of a storm and then calm down as the rains grow heavier.

As we’ve discussed in our posts about hot air balloons, a windy day is the worst kind of flight weather for balloon pilots. The wind makes it difficult to predict where your hot air balloon will go, which is dangerous for everyone. The balloon company cannot risk sending you out on a windy and stormy day.

Reduces Visibility

Although the balloon envelope acts as an overhead canopy when ballooning in the rain, that doesn’t mean the balloon pilot can see clearly. They usually rely on a variometer to tell them whether they’re flying downward or upward, but without being able to see their surroundings as the rains come down, the balloon pilot can more easily get confused or lost.

This can spell bad news for you and your passengers, as the chances of a ballooning accident increase in these kinds of conditions. It’s just like flying a hot air balloon at night, which we’ve also discussed on the blog. The darkness is far too disorienting for confident flying.

Risky Landings

Even if flying a hot air balloon in the rain didn’t carry with it the above risks, the landing still isn’t going to be pretty. Rain makes the ground slick and muddy. As this record of ballooning accidents from 2000 to 2011 shows, most of the reported accidents occurred during landing, up to 81 percent. The cited incidents were the ejection of riders, gondola bouncing, tipping, and dragging.

These things can happen even in optimal ballooning conditions. Now imagine what happens when you add pelting rain to the mix. The balloon pilot usually interacts with the ground crew to choose a landing spot. Due to the decreased visibility from the rain, the balloon pilot might not be able to land exactly in the intended area.

This might not sound like such a big deal, but it very much is. If the balloon pilot can’t accurately eke out a landing spot, you’re at risk of colliding with any nearby obstacles on your way out of the sky. That can include weathervanes, pointy treetops, nearby animals, and–most dangerously of all–power lines.

The abovementioned slickness of the ground would certainly increase your risk of a landing accident. The gondola is far more likely to bounce during a rough landing, and it will slip and skid as well, including when you try to exit. Although the cited gondola injuries from the report were non-fatal, hot air ballooning deaths do happen.

What Happens If You’re Hot Air Ballooning on a Clear Day and It Suddenly Starts Raining?

You see now why hot air ballooning during a rainstorm is very much ill-advised. Yet what if the weather forecasters weren’t calling for any rain and a sudden storm pops up while you’re in the sky? What would happen then?

We can’t stress this enough, but the above scenario is unlikely. Hot air balloon companies are responsible for your safety while you’re in their balloon. They’re going to try their best to decrease liabilities. Even if you don’t have an eagle eye on the weather, they will. If there’s even a chance of rain for the day, the balloon company will either delay your ride until later in the day or postpone it for the next clearer day.

Let’s say though, for example’s sake, that you are out flying in a hot air balloon and it begins raining. The balloon pilot would be willing to take no chances. Even in moderate rain like a drizzle, they’d immediately contact the ground crew to find a spot to make a sudden landing. Your ride would end quickly. You might be refunded depending on how much ride time you missed or you would be able to reschedule an alternate ballooning date.

Final Thoughts

Hot air balloons cannot fly in the rain for a myriad of reasons. The raindrops weigh down the envelope and reduce its temperature so the balloon pilot has to use more propane to keep you in the air. Rain can decrease visibility and make landing bumpier so you’re more likely to end up hurt. Winds may form before a rainstorm, which is also not in the favor of a hot air balloon.

Balloons fly best in low winds and clear conditions, as balloon pilots must have 1 to 3 statute miles of visibility at all times. If your hot air balloon ride gets grounded or postponed because of the rain, it can be disappointing, but remember that it’s for your safety!