Re: [rocketfeuille] height
In reply to:
How much altitude do you all want when jumping cliff faces? What's reasonable? What's too low?
For cliffs and buildings especially, there are many things that are far more important than the overall altitude to impact. Without seeing a particular cliff that you are looking at, no one is going to be able to give you any real feedback on it.
Further information that is really necessary to decide if a cliff is "reasonable" include:
Distance to Landing Area. How far will you have to fly after opening?
Size of Landing Area. Will you need to set up and sink in?
Quality of Landing Area. A quick pound in is ok--if you are landing on a giant mattress (or in deep water). But if you are landing on a 45 degree talus slope, you'll need more time (i.e. altitude) to set up the landing.
Obstructions. What is there to hit? How much altitude will you need to avoid it?
Cliff Angle. Is the cliff underhung? Overhung?
Wind. In zero wind, you may be able to jump lower cliffs. In higher wind you will need to achieve more horizontal separation (which will require more vertical distance--especially if you're a pudgy bastard like me).
Other factors--there are lots. How secure is the launch? How hard is it to get there? How close is rescue in the event of an accident?
Each object is very individual, and evaluating them is about a whole lot more than absolute altitude. In fact, it's one of the most important skills you learn in BASE.
That said, the conventional wisdom is something like:
Reasonable: 400 feet
Too Low: Less than 300 feet
Static Line: 200 feet
The lowest cliff jumps I have personally witnessed over hard earth were freefalls from 173 feet. The lowest cliff freefall I have seen done over water was from 150 feet. These altitudes are pretty much absurd, though, and no one, ever, ought to attempt freefalls at such silly altitudes.
If you are looking at a particular cliff, your best bet is to get an experienced BASE jumper (one who has opened cliffs before) to have a look at it with you.
