Summer is here, and we all are loving the long, sunny hot days. This is the prime skydiving season for many drop zones around the world. However, along with the sunshine comes extra skydiving precautions which we need to take into consideration. Skydiving in the heat can bring on its own set of variables. So while we are all happy to have the hot summer skydiving days here. We also need to educate (or remind ourselves) of the extra precautions we must take during these months. Skydiving in the summer brings along great boogies, lots of jumping and nights around the campfire. We want everyone to stay safe this summer and to be aware of the dangers that can arise while skydiving in the heat.
Impact on your canopy flight
It is extremely important to understand how the hot weather affects your canopy flight characteristics. There are many drop zones around the world that rise up to extremely hot temperatures well over 100 Fahrenheit. In fact, some of these drop zones choose to only open and operate during the early hours of the day, and finishing jumping around lunch time. This is to avoid the hottest temperature times of the day. Which can bring around troubles for canopy flight, aircrafts and for skydivers health!
Density altitude is pressure altitude corrected for nonstandard temperature. As temperature and altitude increase, air density decreases. In a sense, it’s the altitude at which the airplane, or in this case, a canopy wing, “feels” its flying. When temperature and altitude increase and a low pressure system moves through the area, this causes the air density to decrease. Resulting in the density altitude to increase. Along with high temperatures, and pressure altitude, the density altitude in the landing area can increase significantly. For example, you may be landing in air that feels a few hundred to thousand feet higher than it actually is. If you want to dig deeper into the science behind density altitude, check out this post at Skydive Arizona, where they go into depth on the subject.
So what does this mean for our canopy flight? Well, while skydiving in the heat, your canopy will have a faster forward speed and faster decent rate. Be aware of this if you are thinking of performing aggressive manoeuvres, a canopy will lose more altitude in a turn. Your canopy may also experience harder opening forces and a higher stall speed. When flaring your canopy you will notice less power, and therefore a less effective flare. While density altitude is increasing with the heat, your flare with continuously loose power with this increase. Your canopy will be taking the expression “coming in hot”, quite literally.
It is also a subject to keep in mind if you are considering to downsize or to change to a more aggressive canopy. It might be better to wait for cooler weather, rather than learning to fly your new canopy in faster conditions. After the heat wave has passed, now you can learn with more predictable weather conditions and variables.
There is another reason why drop zones with extreme heat close down or operate only in the morning hours. This is because extreme heat causes aircraft performance to degrade. Just like canopies, aircrafts are effected by a higher density altitude.
Some of the effects that a high density altitude has on aircraft include, requiring a longer distance for runway take off and landing. There will also be a much slower and flatter climb to altitude, which consumes more fuel, and lets face it, a miserably hot and long ride for skydivers. Density altitude will reduce propeller effectiveness in the airplane and reduced performance for piston and turbine engine performance. This effect isn’t limited jump planes either. Even the big Airbus and Boeings can be grounded due to extreme heat. Although the threshold is higher with the bigger planes, high temperatures can still ground these flights as well.
Turbulent thermals & dust devils
For sure if you have jumped at drop zones with severely hot weather seasons, you have heard of turbulence caused by thermals and dust devils. Its very hard to predict the forecast the occurrence of thermals, because the conditions can change by the hour. However, these hot weather hazards are generally more common in between the hottest hours of the day, 10 am to 5 pm. During this time the solar heating of the ground is at its strongest. Certain surfaces radiate different amounts of heat. Landing areas are often ploughed ground, rocks, sand and barren land. These surfaces all give off a large amounts of heat. Turbulent thermals and dust devils are more prone to occur over these surfaces.
Thermals are localized, vertical air movements. They will form in situations where the ground is significantly warmer than the air above. Which is quite common in the heat of the summer. The warm air will form from the ground and rise until it has cooled to the air in the encompassing atmosphere. Thermals can be as wide as a few thousand feet, and have a vertical speed of a few hundred to a few thousand feet per minute. And for every rising thermal current there is a compensating descending air flow.
These convective currents will cause bumpy, turbulent conditions, while flying your canopy at altitudes closer to the ground. This unexpected bumpy ride is a result of crossing the boundary between the ascending and descending currents. Updrafts can induce lift in your canopy, resulting in overshooting your landing. While downdrafts can feel like the air support suddenly drops out from beneath your canopy, causing hard landings and undershooting. Skydiving in the heat and turbulence come hand in hand, be sure to talk to your S&TA to learn about turbulence at your DZ.
Thermal turbulence can also result in a weather phenomenon, which is extremely dangerous and life threatening to skydivers under canopy. This phenomenon is called a dust devil. They are very common in the summer in hot areas across the USA. Dust devils are vertical thermal columns, similar to a mini localized tornado. The perfect conditions for dust devil formations is extreme heat, with light winds, clear blue skies and over very hot surfaces, (like the ones mentioned above). Dust devils are especially more frequent and intense in areas where there are a lot of different surfaces with different thermal characteristics, within close proximity to each other. (Think a rocky/sandy landing area with an asphalt road directly beside it).
Once dust devils are formed, it is difficult to indicate which way they will travel. They will move with the speed and direction of the surrounding wind, within the layer that they are occupying. This means a dust devil can suddenly change direction once it reaches a certain altitude. Often this results in a “leaned” appearance/formation. Although dust devils can reach a few thousand feet into the air, they generally are in the range of 100 – 300 feet. The average time span of a dust devil is 4 minutes or less, and they can reach speeds of up to 34 miles per hour. Sometimes when dust devils form, they pick up debris like sand, which make them easier to see. However, often they are invisible with hardly any indication that they are present. Educating yourself on this invisible hazard with skydiving in the heat, is very important!
Canopy flight and dust devils
Flying your canopy through a dust devil can be deadly or lead to severe injury. Dust devils can easily collapse your canopy close to the ground and send you plummeting to the earth. Just as easily they can whip your canopy about without notice. If you are in the situation where you see a dust devil on the ground, attempt to fly your canopy cross-wind to avoid the it. Of course, you must react with caution to avoid a low turn or canopy collision. However, if you do fly into a dust devil, it is recommended to keep your canopy in full flight for maximum pressurization. Use minimal inputs and prepare for a PLF landing.
The safest way to avoid flying your canopy into a dust devil is to maintain awareness of weather conditions. If dust devils are observed near the landing area, consider not jumping. It is a better idea to stay on the ground and jump in more predictable weather conditions.
Protect your gear
Did you know, skydiving gear needs to be protected from the sun? You might be thinking, how do I protect my gear from the sun in the summer sunshine? Well, even these small habits can help reduce the degradation of your skydiving gear. UV damage can rapidly reduce the strength of you canopy fabric, making it easier to tear. As well, the sun damage can quickly fade the beautiful colours of your container and canopy. Help maintain your canopy and skydiving container this summer by following these steps:
- Limit UV exposure. Canopies are made up of mostly nylon, and nylon is extremely susceptible to UV exposure damage. It is estimated that 70-80% of a canopies degradation is a result of UV exposure. So when you land your canopy in the summer sunshine, quickly gather your canopy and head to a covered packing area. If you are not packing immediately, be vigilant to keep your canopy out of direct sunlight while it is waiting to be packed.
- Cover your rig if it is sitting in direct sunlight. This is important both while you are packing and especially if your rig is sitting waiting to be packed. It is very easy to bring a beach towel along with you to the drop zone. Cover your rig and protect it from sitting in direct sunlight. In fact, it is suggested to never leave your gear out in the direct sizzling sunlight.
- Watch out for your sweat! This is a hard one while skydiving in the heat. Of course during the hot summer weather you are going to be sweating. But keeping this tip in mind will hopefully reduce the amount of bodily secretions you smear all over your canopy. Salty sweat can deteriorate your canopy rapidly and highly increase the susceptibility of damage from UV rays. Think about wiping off your body before packing your canopy and laying on top of it to get the air out. And if you give it off to a packer, maybe try to choose one looking a little less sweaty!
So now you are thinking about how to keep your gear protected in the summer heat. You also must remember to protect yourself! Skydiving in the summer, and jumping on multiple loads during the day can leave us dehydrated really quickly. It won’t take long in the high temperatures to become dehydrated, so remember to drink water as often as possible. No one wants to get sick from sun exposure when they can be enjoying summer skydiving!
Very similar to our canopies, our skin does not fair well with extreme amounts of UV ray exposure. Be sure to cover yourself from the sun with a hat, stay in the shade and wear sunscreen! It is no fun trying to put a rig on sun burned skin because you forgot to protect yourself. This summer, only burn your jump tickets!
Keep coming back
Regardless if you are a veteran skydiver or a newbie, each summer season you should be reminding yourself of all the hazards that can arise while skydiving in the heat. This also goes for taking skydive vacations. Perhaps you are normally jumping in a cooler climate, and decide to go for a trip to Arizona to jump. Inform yourself of the conditions you are jumping in, always! We want you to have a great summer season skydiving in the heat and having fun.
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