Alarm clocks go off well before dawn, and we variously stagger out of bed. By the time I finish my shower, my brain is mostly switched on. Heather calls our pilot, Dave, and having received the OK, we head out to the field. We take Heather's car, which is a Bronco II. American readers will recognise this as a somewhat light weight four wheel drivey sort of a vehicle; non-Americans may recall it as the vehicle OJ Simpson used in his low-speed chase.

It's a 20 to 30 minute drive to the field; depending on which specific field we're going to. All the fields are around the edge of the city, where there's more open ground and vacant lots. They are all known to balloonists by some nearby feature - today we're starting at the "post office" field; a vacant lot behind a post office on the north west side of town. As we drive, we note the position of various flags along our route: the two big ones at the gas stations just before the Rainbow curve; the row of small ones at the Mini Grand Prix go-kart place; etc. Balloons take off and land easiest in low winds, and winds that an ordinary person would consider inconsequential are often considered by balloonists to be a problem.

We arrive at the field. It's a good spot: there's room enough to lay out three or so balloons, there are two distant flag poles visible, so you can tell what the wind is doing some way away, it's hard ground covered in a nice sort of gravel, and we have the land owner's permission.

Dave is already here, waiting for us crew to turn up. We put our gloves on, jump out of the Bronco II, say our good mornings, and after a bit, Dave puts up a pibal. A pibal is a helium-filled toy balloon, which balloonists release in order to determine wind direction at different altitudes. Normal people think of the wind as having a single direction and speed, but those sensitised to its vagaries, such as sailors and balloonists, are keenly aware that at different points in space, the wind is doing different things. For sailors, it's two dimensional: they only care about what the wind is doing near the water's surface, and they can look at surface ripples and the sails of other yachts to see what is going on some distance away. For balloonists, it's harder: they care about all three dimensions, and they have less clues.

Weather forecasts, of course, are aimed at normal people; and balloonists generally have great disdain for these forecasts as being almost entirely useless. Slightly more useful are weather reports from airports; but even these are limited: they're aimed at fixed-wing pilots, who only really care what the wind is doing at ground level, at the airfield itself. Nevertheless, the good balloon pilots usually have up-to-date reports from both the city's major airports, in order to give them a general idea of what is going on in the area as a whole.

So we watch the pibal. The wind tends to do more or less the same thing over a fair area, at any given altitude. But at different altitudes, it can be doing quite different things. So a pibal may go south for a while after it is released, then west for a bit, then north. Pilots have a sense for how quickly the pibal gains altitude, and so by watching the pibal keenly for several minutes, can get an idea of what the wind is doing at each altitude.

If the pilot is happy with the wind direction (the wind is not, for example, blowing directly towards McCarran International Airport), we haul all of the balloon bits out of the trailer and start setting them up; but pilots are almost never happy with just one pibal. So we wait for a while, during which time more balloon pilots and more crew turn up; and put up another one. As the pibal recedes into the distance, it becomes a mere speck in the sky, so if you glance away for even a second, you'll never spot it again. If you happen to be driving past a balloon field at dawn, it is quite common to see a small cluster of vehicles and trailers, and a group of twenty or thirty people staring intently at an apparently empty patch of sky.

This is always accompanied by discussion between the pilots, and often if they are unhappy with the wind direction, or the ground wind's speed, they will decide not to fly. So sometimes ballooning consists of getting up incredibly early, driving to the field, standing around staring at the sky, and then going home again.

Sometimes rather than outright chickening out, the pilots will elect to try a different field. That's what happens today. So with the dawn sunlight streaming in from the east, we all pile back into the vehicles and drive off to the west, to Lone Mountain.

This field gets it name from the adjacent park, called Lone Mountain Park, which in turn gets its name from the mountain right next door. And Lone Mountain, of course, gets its name from the fact that it is isolated from all the other mountains that ring the Las Vegas valley; sitting by itself on the otherwise flat valley floor. It's a standing joke amongst Las Vegas balloonists that every pilot has flown over Lone Mountain except Ron. The wind takes Ron in a different direction from everyone else, and while they sail over the top, he gets taken around instead.

More putting up of pibals ensues, and this time, although the ground winds are still "light and variable" (balloonist's least favourite kind), two pilots, Dave and Ron, decide to fly. A third decides against. This is kind of amusing: each pilot decides for him- or herself whether to fly on a given day, and they don't all decide the same way. So some of the pilots float merrily away, while other pilots stay on the ground, cursing the first bunch as reckless. Since pilots decide differently on different days, they have all been in the coward's group at some time or another, watching other pilots fly, with the result that almost every pilot regards almost every other pilot as reckless.

We set up. The first stage is to haul out the tarpaulins, and lay them downwind of the truck. This protects the balloon envelope from stones, dirt, and dust. I have heard that in some other parts of the world, they lay out on grass, which obviates the need for tarpaulins; but standing at the edge of a city built in the middle of the Sierra Nevada, this seems a remote and implausible rumour. The tarpaulins out, we haul out the envelope, which is heavy enough that it requires several people to carry it. Then we bring out the basket, which is even heavier. (Much of the weight of the basket is in the fuel tanks.) The basket is laid on its side, bottom towards the truck, and is affixed to the truck via a rope, to stop the whole assemblage blowing away. We attach the envelope to the basket, and then walk the envelope bag out. As we haul it away, the envelope pays out, and we end with a long thin brightly coloured trail behind us. We spread this out wide, and it now begins to look like an actual balloon.

The next step is putting the top in. Balloons are deflated by means of a semi-detachable top: when the pilot wants to deflate, he pulls a rope, and the top moves inwards from the rest of the balloon, allowing air to escape. It's still attached via ropes to the balloon as a whole, but the air can escape through the gap. That means that whenever we set the balloon up, we must put the top back in, because the pilot has always pulled it out at the end of the previous flight. Some balloons have the top fixed in with Velcro tabs; others use spring clips. This one is the spring clip kind, which makes it kind of fiddly.

Then we haul the fan out of the back of the trailer and start it up. This phase is known as "cold fill", and requires at least four crew not counting the pilot: one on either side of the throat of the balloon, holding it open so that the fan can blow air in; one behind the fan, ready to shut it down or speed it up on the pilot's orders; and one on the crown line, which is the rope tied to the top of the balloon, which is used while the balloon is on the ground to stop it rolling around in the wind. The crown line requires strength, and on windy days it is advisable to put several people on it. The throat positions are noisy, and cold, as you are right in the path of the fan air. In winter, it is customary to foist the throat side closest to the fan off on an unsuspecting newbie.

It takes quite a few minutes to fill the balloon to the pilot's satisfaction. Once this is done, he starts the burner.

This is the everything-happens-at-once bit. The people on the crown line can't see what's going on, as their view of the basket is obscured by the bulk of the envelope. The people at the basket can't hear what's going on, as the noise of the petrol-driven fan drowns out conversation. The general plan is that the pilot, Dave, fires the burner into the throat, aiming a two metre long gout of flame neatly between the two people who are holding the throat open. This is made challenging by the fact that the fan is blowing air in from the left side; in the resulting crosswind, Dave has to aim toward the person on the left to avoid hitting the person on the right! After he gets a few seconds of heat in, he hand-signals the fan operator to shut the fan down. The balloon, now warm, begins to stand up, and it does so with considerable force. The people on the crown line have no choice but to walk forward, allowing the envelope to move gradually upward.

But Dave can't stop burning yet. The balloon is now subject to wind loading on its side, and the wind tends to make an underinflated balloon "dish" inwards. Once this happens, it's very hard to fire the burner without hitting the dished-in side of the envelope, and the pilot may have to abort the whole inflation. In order to prevent this, the pilot must put more heat into the balloon. This will make the air inside expand, and push out harder against the envelope, thus preventing the wind from collapsing it. The flip-side of this, of course, is that the extra heat makes the balloon want to stand up even faster, and makes the balloon as a whole want to leave the ground.

The crew who were holding the throat open must keep the whole throat clear of the burner as the balloon stands up, even though it is out of reach overhead, and then as the balloon gains enthusiasm, must put their weight on the sides of the basket, to hold the whole thing on the ground. And then things are stable once more: the balloon upright, the crown line crew walked in to add their weight to the basket, the pilot putting the occasional burst of heat into the envelope to keep it buoyant. We can now get the radios to perform the radio check, and with the giant envelope above us instead of next to us, can look around us to see how other pilots are doing.

On this particular occasion, the other pilot, Ron, has a problem. When we began setting up, the wind was blowing gently to the south, but now after quite some time spent laying tarps, hauling envelope, and inflating, the wind has changed and is blowing to the north. This was not a problem for us, as we had enough people on our crown line; but the balloon next to us is bigger, and has one less crew member on crown. Balloons present such a large surface area to the wind that even a very gentle wind translates to considerable force. Ron begins his burn to inflate the balloon, and the combined force of the wind loading and this lift is enough to start dragging the crown line crew towards the basket. (It is, in this situation, deeply disturbing to be at the throat of the balloon, and looking down the inside of the envelope, to see the crown gradually moving towards you.) Ron, not immediately realising, continues his burn. Suddenly, he is in a situation where he has a envelope with enough heat in it to want to leave the ground but not yet enough to support itself against the wind, a crown line without enough crew to control it, and delicate balloon fabric marching inexorably towards the hot metal of the burner. It's everything-at-once time again: two of our unattached crew rush over to his crown line; Ron struggles to put out the pilot flames on his burners; and I very gently let go of the side of the basket that I'm holding onto, and having experimentally verified that it's not going to float away without me, sprint to the other balloon's basket, leap up the side, and attempt to shovel away handfuls of fabric from the burner (a trick made possible by the fact that I'm wearing gloves).

It's not possible for Ron to chicken out and abort his inflation, as when the balloon is deflated, it must be laid downwind. Since it's currently upwind, if Ron pulls the top out and deflates, the balloon will attempt to drape itself across the basket, the burners, and his truck. Happily, the extra crown line crew are enough to bring it back under control, and Ron successfully restarts his burners and completes his inflation. The only damage is a couple of marks on the skirt at the bottom of the envelope; the manufacturer had thoughtfully made this part of the balloon from flame-proof Nomex.

Two balloons now bob gently, upright. The pilots converse briefly, there is the usual process of swapping people in and out of the basket; removing people who were merely acting as ballast, adding people who are going to actually fly. And then the pilots add a little extra heat to the envelope, the crew let go of the basket, and the balloons sail slowly, silently away.

Next: Ballooning Too