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BASE Jumping: Articles: General: Building Jumping - A Primer

Building Jumping - A Primer updated

by BASE 460

Buildings are some of my favorite sites to jump and especially to open. I generally prefer occupied buildings, which is slang for a building that has been completed. I like the challenge and the feel of the experience. I will only give a few access clues since I don't want everyone to know all my tactics.

I am in no way advocating for anyone to break the law. This information is for entertainment purposes only.

My first building was in 1995. It was a freefall from a 280 foot control tower at an active international U.S. airport. I opened the site. Airliners taxied next to me. It was interesting to say the least. Also, I had no insider help to open or jump this object.

I have settled down from building jumping due to my job and I need to replace my worn out parachute before resuming further urban parachuting. Some of this information may be dated but the basic philosophies should still hold true.

This article is a building jumping primer. I try to cover many potential scenarios as part of this tutorial. With the intent of doing many building jumps, it may be to your advantage to find a building jumping mentor. It may be very difficult to find one willing to work with you though.

Building jumping can be very rewarding. Jumping a building is a laudable feat. My building jumps were best jumps I've ever done and also the most intense moments of my life. There are other jumpers with far more building jumps than I have who may have better techniques and may disagree with me on some points. The gear and general techniques have improved so much that the chance of a 180 is much lower now than in the past. I view my techniques as more conservative than later BASE generations who now have the advantage of much better gear and ready access to body armor.

Despite the impression I may give you, buildings are very technical in nature from both a parachuting aspect and a subterfuge aspect. Occupied buildings are even more technical. Jumping occupied buildings is very high-stress for a variety of reasons but many of them are related to the fact that it is extremely difficult to be discreet. They are definitely not for the casual BASE jumper. In addition, if you are doing this with attention seeking in mind, trying fueling your ego by becoming a rock star or something. Being low key is very important. There was one BASE jumper in Arizona who had several hundred building jumps from various sites and no one even knew this was happening. He didn't let anyone know except his trusted inner circle.

Unfortunately, in the post - 9/11 era, buildings – especially those occupied by companies or organizations having ties to the Middle East – have significantly tightened their security by limiting access to stairways and sensitive areas of the building, like the roof. The government has been taking communications infrastructure a lot more seriously since 9/11. Tall buildings tend to have antennas and satellite dishes on top.

To emphasize the importance of communications in the eyes of the U.S. government, most antenna towers have a repeater for police communications. And some towers are a part of a communication infrastructure related to both Homeland Security and the F.A.A. Disruption of such communications from something jump related could potentially drive the issue to the state legislatures and national legislature. Consider the incident of a BASE jumper who rode a BMX bike off a platform from a well known antenna site. The jump was filmed from several angles including the ground. When the jumper separated from the bike, the bike actually hit the tower at a high rate of speed a few hundred feet from the ground. The jumpers on the ground laughed about it. The video was released for sale to the public. It is probably benign since no communications infrastructure was damaged but that is an extremely risky behavior given the fragility of access to many sites. I pray that video does not come back to haunt us.

Because of the new era of substantially increased security, getting a building jump now is more difficult that ever. That combined with current easy access to legal sites nationally and internationally has dampened many a jumper's interest in jumping buildings.

Some jumpers will jump a 300 foot building next to some 800 foot buildings simply because they have no ability to get access. I always look at them with a ridiculous expression and say "hey, why would you steal a Ford Pinto parked next to a bunch of Ferraris when it's the same crime for both?"

The definition of a building is a little outside of the scope of this but it generally has to be occupied or occupy-able and it must create significant wind turbulence around it. It is not considered a building jump to jump from a construction crane next to a building unless in my opinion the building can be readily hit immediately after the canopy opens.

The techniques I am going to describe can hopefully become second nature and you may not have rely on all them once your building jump skills have increased.

Before going into some of the tricks of the trade, knowledge of the winds is critical on building jumps. Most experienced building jumpers will not jump in any wind above 5 mph when jumping in a downtown area in the center of the city unless they truly know the characteristic winds. This is because of unexpected turbulence and funneling of wind. This is especially true around buildings with sharp corners. Smooth circular buildings are much more ideal.

Isolated smooth circular buildings are the most ideal case. Second to that is an isolated typical building with corners. Third in difficulty is the building on the edge of a big city. The most difficult scenario is jumping in a big city downtown area. The maximum wind limit of 5 mph in the center of a downtown area can obviously be adjusted given the easier cases and your prudent judgment based on careful analysis of the local wind conditions.

To help your appreciation of the winds you might encounter, try a CRW jump and let another jumper steal your air. Now imagine the same encounter next to large buildings.

As Adam Filipinno once commented, "a good BASE jumper is a thinking BASE jumper." You need to start intimately understanding what the winds do. I would suggest you buy a book on micrometeorology like Understanding the Sky by Dennis Pagen and study it.

Ancillary to Pagen's book is some optional internet viewing of the website http://www.mems.rice.edu/TAFSM/PROJ/AS/MDCM/

There are several things that are important for jumping buildings:

1) winds near the ground

2) winds near the opening altitude

3) winds near the top of the building

4) winds for the canopy flight to make it to the landing area.

Winds near the ground around a building have always been confusing for most people. My personal favorite technique is to buy a small helium gas bottle from Walmart, etc. and release balloons at strategic points to understand what the wind is doing in the bottom 100 to 200 feet. There can be drafts that drop a jumper very quickly onto concrete, asphalt, power lines, and other such hazards that accompany a building. Incorporate this information into your plan. As BASE 38 says, "Plan your jump. Jump your plan." Obviously as your skills and instincts improve, you can guide yourself in whatever you feel is appropriate.

Winds near the opening altitude may be impossible to predict. Obviously, a good horizontal launch with enough delay can place the jumper further away from the object than a poor launch. A good launch and a sufficient delay can allow more time to deal with a serious off heading opening. A good horizontal launch can result in 15 feet per second horizontally.

Winds at the top provide some basic information but it is subjective. Drop some heavy napkins with one end tied into a knot to weight it or wrap the napkin over something like a small stick so it doesn't float all over the city. Napkins floating all over the city might be cool to watch but it doesn't tell you what the winds are doing in the region of your jumping interest. I have seen newspapers float in a turbulent eddy wind current at several hundred feet for hours at a time.

The downwind side of a building is sometimes called the "wind shadow" and can result in some very unexpected winds. A friend of mine, BASE 38, jumped in the wind shadow in mild to moderate winds and after flying out about 20 feet outward from the building, he felt a head wind that kept his canopy from making much headway. It was a direct result of the eddy wind current directing the wind directly back toward the building. This same friend on another jump jumped into a 3 mph headwind because of the much more favorable landing area and he didn't have to deal with the eddy head wind current in the wind shadow. Coming out of the wind shadow can be dramatic and I have actually felt like I was taking off like a rocket going forward, even rising in altitude under canopy.

Imagine an isolated square building with a 10 mph wind as in the diagram below. Ideally, the exit should be from a corner if possible to ensure 270 degrees of heading clearance. If you jump from a face, you reduce the heading clearance to 180 degrees. The weighted napkin wind drift indicators will allow you to make a judgment call regarding which location is ideal for the exit after considering the effects of a 180 or bad off heading open.

Basejumping Article Image1_large
Buidling Wind Diagram 1
BASE 460

Exiting from point C would result in a headwind near point D. It would also only provide 180 degrees of object clearance. I would now choose points A or B. The landing area and surrounding area will dictate either A or B as exit points. I will choose exit point A for the sake of argument. Jump outward from point A to insure 270 degrees of clearance. The sidewind now works to your advantage or at least it doesn't work nearly as badly against you. If you have a bad offheading to the left, you will quickly arrive at point D with some jumper corrections. You can (hopefully) deal with the headwind, but that's better than being at point C, i.e., an imminent object strike. After exiting point A, if you have a bad offheading to the right, you may end up at point E. Upon correcting to the left, you will quickly approach point F and you can now start flying to setup a landing pattern.

Basejumping Article Image2_medium
Building Wind Diagram 2
BASE 460

Now imagine the other extreme with the winds: the winds approaching the building 45 degrees relative to the faces. This is a much more complicated situation and there are many potential scenarios for jumping. The weighted napkin wind drift indicators will allow you to make a judgement call for which exit location sucks the least among several potential exit points. My suggestions below may be completely wrong in your specific case and given the presence of other buildings in the area.

Consider what the consequences of a 180, a 90 left, and a 90 right, or other off heading angles on every conceivable exit as you see fit.

I would suggest three different exit directions from point A. The directions are E, F, and G. For the sake of argument, I will assume the winds are light, maybe 10 mph. Consider exiting from point A toward point G. With a 180, I would try to correct the heading to get to point E or L or whatever direction you feel is appropriate given your wind analysis. If I had a 90 right, I would correct to the left and try to end up at point G and then to point F. If I had a 90 left, I would try to proceed to point F or E.

If I jumped toward point F and had a 180, I would choose either to turn left or turn right depending on the strength of the winds. If I turn left, I may be able get to F or E, an ideal location and prepare myself for a future beer moment! If I turned right, I would try to get to L and continue turning right to get away from the building.

If I jumped toward point E and I had a 180, I would turn left and try to get back point E or F. If I had a 90 right, you are in the ideal zone to proceed to points F or E. With a 90 left, you will end up and L and maybe D. You are then in the wind shadow and you will have to use your best judgement to escape from it. I have done this before and things quickly became hazardous.

Jumping B, C, or "I" doesn't seem ideal all around but it also depends on your wind analysis. B would be good if the winds were very light at the sacrifice of having 180 degrees of clearance and having to deal with a potential head wind while coming out of the wind shadow.

One of the things I do before a technical building jump is simulate the jump from a local antenna (or your local bridge). I prefer antennas since the ones local to me have huge clear landing areas to provide good measures of distances and flight angles for the planned building flight pattern and landing approach. This requires weather that will be similar to that encountered on the building. There is one building about 750 feet tall I want to do that will require me to fly about 1500 feet out past several buildings to make it to the best landing area. It's a "cross country" building jump! Knowledge of the height of the building and the relevant distances is important for technical building jumps. This is why I use my antennas as simulation tools when I need to hone my building jump canopy flight skills.

To do that cross country urban BASE jump, realize that passing over other building can cause strange updrafts and strange turbulence. You should try to use updrafts to your advantage to make it a distant landing area given the prevailing winds! Note anything that might affect your canopy flight to the landing area.

I generally find that the winds die significantly immediately after a significant storm passes through the area. The local atmosphere has exhausted itself and the winds will be calm. There are a couple complicating factors: the landing due to the wetness, which could easily break a wrist or tailbone (ouch!), and the reduced canopy lift due to the moist air. Water does reduce the friction of contact with a glass or concrete building which reduces the chance of death given an object strike, but most building faces have too much texture to provide any advantage to jumping a wet building.

Be aware that if you strike the building, you may break the glass windows and you may even fly through the glass into the building. I had a friend (BASE 95) who flew through the glass and landed on a man's desk. The parachute hanging outside the building re-inflated, dragged him out, and he landed on a 2 story building near the original site. If you are caught, be aware that the building owner may sue you for the replacement of the glass. Fees as high as $5000 to $10000 are not unheard of in previous building strikes that resulted in building glass damage.

Besides a felony arrest for jumping a building under construction, there is another reason I am cautious about jumping buildings under construction. A building strike could easily be fatal since the side of the face is so textured. Also, the rebar on the ground can be fatal. BASE 46 developed the slider down line modification system after having a line over while jumping a building. A piece of steel rebar pointed vertically to provide the structural support for eventual concrete penetrated his leg through his femur. He was in the hospital for over a month and it nearly cost him his life.

One of the nice outs for landing in downtown city are parking garages but they can be much trickier to deal with than you think.

Before attempting an occupied building or any significant object, remember that "piss poor planning means piss poor performance." I was once to do an early evening jump from a big building downtown with two friends. I cancelled the jump because we were running out of time and everyone seemed disorganized. This was before everyone had cell phones. My ground crew, a very experienced jumper, showed up in the landing area. He said to himself either they didn't jump or they are in jail. The landing area had about 2000 police officers who were having a memorial for an officer killed in the line of duty.

You of course always have the option to walk down from a jump even if you are on the edge. Regret is a terrible thing while spending time in a hospital bed or jail cell. Jail will always be preferred over a serious injury. Losing your gear will also be preferred to going to jail or a serious injury. I have had to dump gear while fleeing on foot from officers.

BASE 460

• Dedicated to the BASE jumpers who showed me some of their techniques.

• Some of the subterfuge explanations were borrowed from Walt Appel's "I am not a smart man when I'm drunk" thread on dropzone.com during one of our scouting adventures. It's a must read and it's one of the funniest things I have ever read.


Submitted by BASE 460 on 2007-07-20 | Last Modified on 2010-04-13

Rating: 12345   Go Login to rate this article.  | Votes: 13 | Comments: 4 | Views: 9694

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4 Comments CommentAdd a Comment

 460
460
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 2007-08-07
5 out of 5 stars Needs the figures.
 Bartblabla
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 2007-11-10
yeah illustrations would be nice, it's interresting but without the pictures im lost

thx
 WhisperingWind
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 2008-04-25
does anybody have the diagram? vital :)
 brianfry713
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 2008-06-13
Diagrams
http://www.basejumper.com/cgi-bin/forum/gforum.cgi?do=post_attachment;postatt_id=84774;
http://www.basejumper.com/cgi-bin/forum/gforum.cgi?do=post_attachment;postatt_id=84775;

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