What is the Ideal Hot Air Balloon Flying Weather?
POSTED: Friday, May 23, 2014 - 10:38am
UPDATED: Friday, May 23, 2014 - 11:07am
Wind and other weather conditions will be analyzed by pilots before taking off in this weekend’s KLAQ Balloonfest
Friday, May 23rd, 2014 — I am currently looking at the wind forecast for this weekend preparing for my 17th year as “Weather Wizard” for the KLAQ Balloonfest. This year the balloon launch is at the Maldonado Maze in La Union, New Mexico where over 20 hot air balloons will launch into the early morning sky! Balloon launch viewing and parking are completely free! The launch event takes place every morning this Memorial Day Weekend from 6 a.m.. – 10 a.m.. on May 24th, 25th and 26th. I am always excited to see the special shape balloons and this year’s theme is “Out of This World.” One balloon is shaped like an "Astronaut"; another is called “American Rocket” and third is “Planet Earth”. In today’s “Weather Talk” I will take a look at what are the ideal conditions needed in order for the hot air balloon pilots to fly? Also, what are some of the hazards they need to watch our for. I did a little research, talked to some pilots and here is what I found out.
More balloon flights are canceled due to wind than for any other reason. The wind is the number one factor that effects every phase of a balloon flight, from the inflation, the flight to the landing. Hot Air Balloon pilot’s ideal flying speeds are 4 to 6 miles per hour. They will still take off in the maximum safe winds of 8 to 10 mph. I have seen a few brave pilots take off in 15 to 20 mph, but it is not advised or is it as safe.
THE INFLATION WINDS
When the crew and the pilots are inflating the balloons is filled cold air is blown in using a fan. The balloon fabric is just like a giant sail. Winds that are blowing at 10 mph or more cave the side of the balloon in making it very difficult to almost impossible to fill the balloon. This sail effect places tremendous loads on both the fabric and the basket. The balloon will roll and whip around which to safe for the balloon or the crew. The force of the wind can be 3-10 tons depending on the size of the balloon.
IN FLIGHT WINDS
A balloons flight path and the distance it will travel are dictated solely by the wind's speed and direction. Upper level winds are usually stronger than the winds at the surface. The stronger the winds aloft, the farther the balloon flies. This can be a problem if high winds carry the balloon into areas that are unsuitable for a landing. Some of these not so good locations include housing or metropolitan areas, areas with many trees, restricted airspace, and large bodies of water. Plus the chase crews have to drive a longer distance. The Chase crew follows the balloon in a vehicle and then helps safely deflate the balloon, fold it up and put back in the trailer.
I remember one KLAQ Balloonfest when I got the chance to fly and we landed in strong winds. Kind of scary! A balloon's speed across the ground will be the speed of the wind it is flying in. The surface winds had picked while we were in flight. When the pilot went to land the basket was sideways bouncing through the cacti and the brush. Branches were flying into our faces. I was riding with a girl form Chihuahua, Mexico who was praying and saying all kinds of things in Spanish as we were bounding through the desert! A balloon does not have brakes so it relies on the friction of the basket dragging along the ground to come to a stop. During a landing in high winds, the basket will skip, drag and bounce along the ground. Believe me when you are at the mercy of the wind to stop, it is not much fun!
UPPER LEVEL WINDS
Pilots also have to think about what the wind is doing at altitude as well. This is perhaps the most confusing aspect for our passengers. As a launch meteorologist or a pilot, we look at winds at the surface and the winds at 1 to 9,000 feet. The balloons do not plan on going to 9,000 feet but looking at the winds at 9,000 to 15,000 foot level help determine if the pilot might encounter issues such as wind shear, turbulence, or strong surface winds later on. There may be barely a breeze at the ground level but upper level winds of 18-20 knots or 20+ miles per hour can be strong enough to cancel and reschedule a flight.
RAIN OR STORMS
Pilots do not fly in rain or storms. An airplane pilot is able to turn around, alter its course or fly above a storm. A hot air balloon is pulled into a storm. A building thunderstorm has winds that pulling air towards and into the storm. A dying thunderstorm has very strong, damaging winds that blow out from the storm. An outflow boundary is a strong line of winds that blow 60 to 100 miles away from where the storm was in all and any direction. These winds can reach speeds of 40 to over 100 miles per hour. This can be very dangerous to a balloon and its pilot/passengers. If storms are forecast or there are storms within 100 miles pilots will cancel or reschedule their flights.
Hot air balloons fly because hotter air inside the balloon is "lighter" then the surrounding air causing the balloon to float upward. The more heat, the higher up you go. The outside air temperature is going to affect balloon flights. A balloon will fly when its temperature is normally around 140 degrees above the outside air temperature. So, the colder it is outside, the less heat it takes to fly and conversely, the hotter it is outside, the more heat it will take to fly.
Outside Air Temperature + Heat it Takes to Fly (140º F) = Temperature Inside the Balloon
90º F + 140 F = 230º inside the balloon
The smaller the balloon, the less lift capacity it will have and the hotter it must be inside the balloon for it to fly. The maximum continuous operating temperature for most hot air balloons is 250º Fahrenheit.
Pilots are required by the FAA (Federal Aviation Administration) to fly under Visual Flight Rules or VFR. If the conditions are foggy or hazy, or here in the desert dusty, the visibility must be 1 to 3 miles. If the visibility is lower the balloons do not fly.
So make plans to come out to the Maldonado Maze in La Union, New Mexico for the year’s KLAQ Balloonfest Balloon launch. The whole family will have an excellent time and there are some excellent photo opportunities. You can also volunteer to be part of a balloon crew that helps set up the balloon, chase and pack up the balloon as well. I am looking forward to giving my morning weather briefings and helping to announce the balloon launch as well.
Let’s hope for light winds and sunny skies!