Ridge lift

Where the rising air in front of a hill is, how much wind it takes, and why the air behind the crest is somewhere you never go.

In this lesson you will

One evening at the hill the breeze comes straight up the slope, and instead of gliding down to the landing field you stay level with launch, then rise above it. That is ridge lift, and most pilots first learn to soar in it.

The same wind can also push you back over the hill, into air that wants to put you on the ground. This lesson is about the air; flying the beats comes in Ridge soaring.

What makes ridge lift

Wind cannot go through a slope, so it goes up and over: the steeper the slope and the stronger the wind, the faster it rises. That is ridge lift.

You soar when the air rises faster than your wing sinks. In makers’ figures a school wing’s minimum sink is about 1–1.05 m/s200–200 ft/min¹²; at trim speed it sinks about 1.2 m/s240 ft/min¹. Check your manual.

It takes a ridge: much of the wind flows around an isolated hill, giving little lift. The best soaring ridges are long³.

The shape of the lift band

The lift band is the part of the sky in front of the ridge where the air rises fast enough to hold you up. Carry its shape in your head:

Below the top, the best lift is close to the slope⁴.
Above the top, the lift moves further out in front of the ridge the higher you go⁴.
More wind makes the band taller and pushes it further out⁴; in light wind instructors find it stays close to the slope⁵.
How high: at most two or three times the ridge height, for sailplanes⁴. In the light winds students fly in, expect it to end not far above the top.

Instructors find that faces square to the wind work best and a spur jutting into the wind gives almost none⁵. In an angled wind, the side of a bowl that faces into the wind works, and the side sheltered from it can have sink³. A ridge upwind can put a slope in its wind shadow⁶.

Figure: A teaching model of ridge lift over a ridge 100 m (330 ft) high. Notice the band hugging the slope in light wind and leaning out as it rises, the arrows turning from rising to sinking at the crest, and how much faster the wind is just above the top. Try the presets.

A teaching model of ridge lift over a ridge 100 m330 ft high. Notice the band hugging the slope in light wind and leaning out as it rises, the arrows turning from rising to sinking at the crest, and how much faster the wind is just above the top. Try the presets.

Don’t chase the lift into the hillside. The DHV’s rule is to keep at least 50 m165 ft from the slope whenever you can, because even a docile wing can lose 20–40 m65–130 ft in a big disturbance⁷. If the only lift is closer, it is too light for you today.

Slope and wind direction

The FAA’s handbook for sailplane pilots calls a slope of about 1 in 4 (about 14°) ideal; gentler slopes don’t push the air up hard enough for a sailplane. Very steep faces still work, but make turbulent eddies along the lower slope and close to the face, so only the upper part is useful⁸. A slow paraglider can use a gentler slope, but only in more wind, which costs margin (try the Gentle slope preset).

The lift is best with the wind blowing straight onto the ridge. The same sailplane handbook says it still works 30–40° off in one chapter and within 45° in another⁹. Only the part of the wind blowing across the ridge pushes air up it, so the further off the wind, the weaker the lift. One school warns that an angled wind also makes the hill rougher, because every spine and gully can make rotor; for launching, USHPA’s P2 limit is wind within 25° of straight up the slope¹⁰.

Too light, workable or too strong

The wind you need depends on the slope, the ridge and your wing. One instructor’s example puts the threshold to stay up at about 16 km/h10 mph, with a slow descent at 13 km/h8 mph⁵: an illustration, not a rule. The BHPA notes that UK hills are usually soared in about 25 km/h16 mph, and that paragliders are limited to relatively light winds of about 28 km/h17 mph¹¹. Those figures describe rated pilots: student limits are lower (see the block below), and your instructor’s are usually tighter still.

	What you see and feel	What it means
Too light	Lift only close to the slope; further out you sink.	A thin band against the terrain. Fly out and land.
Workable	You climb above the top well out from the slope, and still move clearly forward into wind.	A band above the top and a real margin.
Too strong	Strong lift, but into wind you barely move, and you need a big crab angle to hold your line¹².	Little margin, and more wind higher up and over the crest.

Strong wind also means rough air. Guidance written for aeroplanes calls about 37 km/h23 mph at ridge level strong, with turbulence, strong up- and downdraughts and rotor¹³; for you, that is your whole trim speed.

Standards differ Wind limits that apply while you are a student

Common ground: Your instructor sets the limits on the day, usually tighter than any published figure. SafePro, the international reference, keeps first-stage students to stable conditions with light, smooth headwinds¹⁴.

USHPA (USA): Recommended P2 limits: base wind at most 19 km/h12 mph, peak gusts at most 24 km/h15 mph, and gusts rising by no more than 8 km/h5 mph in 5 s¹⁵.
BHPA (UK): No published numeric student limits for paragliding: your school sets them¹¹.
APPI (international): A maximum of 15 km/h9 mph for ground handling at all three student levels; no separate in-flight figure is published¹⁶.

Summarised from each body’s published material, which changes over time. Check the current official documents and follow your school.

Instructor's note What launch won’t tell you

On high ridges the lower slopes can be almost calm while the upper slopes are in strong wind¹⁷. On sunny days thermal sink can cancel the ridge lift or roll you towards the slope, and unstable air plus strong wind is dangerous for a new pilot. Always plan for the lift to disappear¹⁸.

Penetration margin

Flying into wind, your speed over the ground is your airspeed minus the wind. When they are equal you hover; when the wind is stronger you go backwards, which is how pilots get blown back over a ridge¹⁹.

Your hands-up trim speed is the speed you can count on: about 37–38 km/h23–24 mph for current school wings²⁰ (check your manual). So your penetration margin is:

Penetration margin = trim speed − wind speed.

At 37 km/h23 mph in an 18 km/h11 mph wind, you move forward at about 19 km/h12 mph. We know of no published minimum margin; your instructor will tell you what they want to see. Know what eats into it:

Height. The wind usually strengthens as you climb¹⁷.
The crest. The wind speeds up over the top. For a smooth ridge 100 m330 ft high, an engineering guideline gives up to about 80% more wind just above the crest²¹; instructors estimate it is often 8–11 km/h5–7 mph stronger on windy days²². Either way it can be more than your speed bar adds. This is compression.
Brakes. One training sheet gives about 34 km/h21 mph at minimum sink against 37 km/h23 mph hands up²³.
Gusts, which add to the average for seconds at a time.

The speed bar is a way out of trouble your instructor teaches you (Blown back and cloud suck), not a reason to fly in more wind. In the figure, compare the Workable and Too strong presets: more lift, but no margin just above the crest.

Keeping track of your margin

Before launch, compare the wind with your trim speed.
Cue A wind meter, the windsock, and how fast other wings move over the ground.
Why Many instructors prefer a wind meter to the feel on your face²⁴.
On every beat, watch your crab angle and your progress along the ridge.
Cue You point further out to hold your line, and the ground slides past more slowly.
Why Both mean the wind is building¹².
When the margin shrinks, fly forward, away from the ridge, and down towards the landing field, with your instructor on the radio.
Cue Into wind, the ground moves back under you again as you get lower and further out.
Why The wind is weaker lower down¹⁷; waiting for it to ease is how pilots end up behind the hill.

Common mistake Climbing to the top of the band in a building wind

Symptom: The lift is smooth and strong, so you keep climbing; into wind you barely move.
Cause: The wind is stronger higher up, and lovely lift hides it.
Fix: Treat strong lift with a small margin as a warning. Stay low and well out in front, and come down as soon as the crab angle grows.

Common mistake Scratching close to the slope on a light day

Symptom: You beat back and forth metres from the hillside, a wingtip near the bushes, and still sink.
Cause: In light wind the only lift is right against the slope.
Fix: Keep your distance. If you can only stay up close to the hill, fly out and land. That is a good flight, not a failure.

Behind the crest: the lee

Behind the top, the air follows the ground down the lee side, getting more turbulent and pushing you towards the slope. Near a steep ridge in strong wind the sink can reach about 10 m/s1,960 ft/min or more, and a flat top is no refuge²⁵. On steep lee slopes, from about 15–18°, the flow breaks away into rotor²⁶. A gentler lee slope still sinks and is often rough: treat every lee as no-go²⁵. Rotor, venturi and compression explains more.

Safety-critical Stay in front of the ridge

Never fly on the crest or below it on the downwind side. Turn away from the ridge every time, because a downwind turn, even above the top, can carry you over the crest into heavy sink. Crab into wind so you don’t drift over the top. Instructors add: never fly above and behind high cliffs²⁷. As a student, stay in front of the summit whatever the wind.

Why beginners don’t top-land

Top landing saves the walk up, but stacks everything in this lesson against you: the strongest wind just above the top, sink and rotor just behind it, and an approach low over rising ground.

The DHV reserves top landing for practised pilots at sites they know, trained with an instructor on the radio in smooth air, always ready to go around. SafePro tells soaring students to avoid it²⁸. A slow approach is especially dangerous there: below minimum speed the wing stalls²⁹.

Standards differ When ridge soaring and top landing come into your training

Common ground: Soaring starts under an instructor’s control in smooth, steady wind; top landing comes later, where it is easy, with an escape option. SafePro lets students soar only under instructor control³⁰.

USHPA (USA): Ridge soaring is a special-skill endorsement, which includes soaring in a crosswind without stalling on the downwind legs³¹.
BHPA (UK): Club Pilot training includes pre-soaring and soaring phases³², and its environment exam covers top landing³³. After the rating, the Foundation syllabus asks for top landings at several sites³⁴.
APPI (international): Ridge soaring is introduced at APPI Pilot level³⁵. The Dynamic soaring certification needs at least 10 ridge-soaring flights in steady wind and an easy top landing on your own³⁶.

Summarised from each body’s published material, which changes over time. Check the current official documents and follow your school.

Questions students ask

Why does the wind feel light on launch but strong once I’m up?

You stand in the slowest air. Many schools warn that the wind on launch can be up to about 10 km/h6 mph weaker than a few metres up³⁷, and above the top it usually keeps strengthening¹⁷.

How is ridge lift different from a thermal?

Ridge lift is made by the wind and stays in front of the slope. A thermal is made by the sun, comes and goes, and drifts with the wind (see Thermals).

What about a cloud sitting on the ridge?

Moist air pushed up the ridge can form a cap cloud. If it lowers onto the ridge, the updraught that holds you up can carry you into it, out of sight of the ground³⁸. Stay well below it, or land.

Key points

Ridge lift is air pushed up a long slope by the wind; you soar where it rises faster than your wing sinks (about 1 m/s200 ft/min).
Below the top the lift is close to the slope; above it the band moves out and up. Keep your distance.
Lift is best with the wind straight onto the ridge; the sailplane handbook accepts 30–45° off, with weaker lift. For launching, USHPA’s P2 limit is within 25° of straight up the slope¹⁰.
Penetration margin = trim speed − wind. Higher up, and just above the crest (up to about 80%), the wind is stronger: watch your crab angle and come down early.
Rated pilots soar in winds above student limits; your instructor’s limits come first.
Behind the crest lie sink, turbulence and rotor. Stay in front of the summit and turn away from the hill.
Top landing is an advanced skill for later, learned with an instructor.

Ground to Solo is a study aid. Paragliding is learned in person with a qualified instructor at a recognised school; nothing here certifies you to fly.