A paragliding pilot or delta wing does not need a laboratory to know how the atmosphere is: it is enough to look up. The clouds are the visible result of what the air does. They tell us where it goes up, where it goes down, how much moisture it has and, most importantly, whether the day is going to be a gift to fly or a trap.
The 10 grand: international classification
High clouds (6,000-12,000 m):
- Cirrus (Ci): fine, white, like brushes. Solas do not bring problems, but if they multiply they announce time change at 24-48 h.
- Cirrouculus (cc): small flakes aligned, "fish scales."
- Cirrostratus (Cs): transparent veil that produces halos. Preview warm front.
Average clouds (2,000-6,000 m):
- Altostratus (As): grey-blue layer. Bad day, stable, few thermal.
- Altocumulus (Ac): borreguitos. In the form of "castellanus" early they warn evening storms. The most famous sign to distrust
Low clouds (< 2,000 m):
- Stratus (St): low grey mantle. It doesn't fly.
- Stratocumulus (Sc): sky covered with grooves. Flat day.
- Nimbostratus (Ns): dark grey, rain. The couch day.
Vertical development:
- Cumulus (Cu): the pilot's cloud. White, flat base, cauliflower.
- Cumulonimbus (Cb): the monster. It can reach 12 km. The only cloud that can kill you directly.
The family clusters, from friend to enemy
- Cumulus humilis: low, wider than high. The pilot's friend. Organized thermal, safe day.
- Cumulus mediocris: height almost equal to width. Powerful thermal, XC possible.
- Cumulus confreestus: higher than wide, cauliflower tight. Very unstable. Many come down when he shows up.
- Cumulonimbus: congenital with anvil. Storm: get away 20 km.
Cloud that are direct danger
- Lenticularis: stationary dish on mountain. Mountain wave, strong wind going through. Don't fly untrained.
- Rotor cloud: clusters torn under the lenticular to leeward. Extreme turbulence.
- Foehn gap: clear to leeward. Strong wind down and dry. Don't take off.
- Cap cloud: cloud wall attached to the crest.
- Pileus: fine cap on cluster. Thermal pushes down.
- Mammatus: bags under mature storm. Far away.
- Virga: rain that evaporates. Cold descent, unexpected rachas.
How a thermal cluster is formed
- Formation: the sun heats the ground, the air rises as a bubble (thermal). When you reach the dew point, you condemn: the cluster is born.
- Madurez: flat and dark base, cauliflower grows in vertical. Active thermal.
- Dissipation: bounded edges, curved base up ("smiles base"). Don't come up
Rule: white clouds with dark and flat base = up. Grey clouds with curved base = does not go up.
When the wind in height is constant and the instability is uniform, the clusters are aligned in parallel rows. Under each row there is continuous descent. It allows you to cross tens of miles without turning.
Visual signs used by the expert
- Tops sharp and bright → young cloud, strong descent.
- Tops clear → dissipating.
- flat dark base → thermal feeding.
- Base with rain or virga → caution.
- visible anvil → cumulonimbus, stay away YA.
- Mammatus → mature storm, severe turbulence.
Height of the cloud base (cloud base)
Espy formula: height (m) = 125 × (Temp - Rocío) both in ° C.
Example: 14h, 25 ° C, dew 10 ° C → cloud base - 125 × 15 = 1,875 m above the ground.
cloud suction: the invisible trap
A sloppy pilot can be aspirated to + 6, + 8 m / s or more under a base. Inside it is lost visibility, the candle can be folded, in cumulonimbus there is lightning, ice and asphyxiation.
Gold rule: 300 m minimum below base, 300 m horizontal edges. If the vary does not go down by turning with ears and B3, go out by the side by accelerating.
Basic synoptic meteum
- Anticyclone (H): air descends, few clouds, stable time. Good to fly in summer.
- Depression (L): air rises, clouds, fronts. Bad to fly except post-front windows.
- Isobaras very together → a lot of wind. Spread → soft.
Brains:
- Cold: abrupt advance, cumulonimbus, storms. Never fly in front or during.
- Warm: slow, progressive coarse sky. Rain day.
- Ocluded: persistent cloudy.
Local breezes
- Valley (anabatic): day, sunny slopes warm, wind rises. He's holding ridge.
- Mountain (catabatic): night, low cold air. Evening danger: wind is reversed and accelerated.
- Sea / land: day sea → land; night inverted.
- Glacial catabatic: day and night, violent rachas.
- Foehn / zonda / chinook: warm dry wind to the mountain range. Don't fly.
- Breezes convergence: two breezes collide, line of long descent. Gold for XC
Key meteor indicators
- CAPE: available energy. 300-800 J / kg = classic XC; > 2500 = storms.
- Lifted Index (LI): < 0 unstable good; > 4 very stable.
- Thermal gradient: > 6.5 ° C / km in low layer = good convection.
- dew point: defines cloud base.
- Cizaladura: > 15 kt / km = broken thermal.
- Investment: layer where T increases with height, sets ceiling.
Critical hazards
- Storm (Cb): stay away 20 km.
- hail: destroys candles.
- Microburst: violent descent, 200 km / h to the ground.
- Gust front: cold blast before storm. Dust line, flag changes. Plegar and land.
- Low roof: risk getting into cloud.
- Excessive wind: > 25-30 km / h at 1,000 m complex; > 40 km / h do not take off.
Recommended Apps
- Windy.com: global, multi-model, easy display.
- Meteoblue: thermal profile per site.
- Meteo-Paragliding: Europe-specific AROME.
- XCSkies / Skysight: paid, maximum accuracy for serious XC.
New Protocol
- Vispera: Windy or Meteoblue. Surface wind, 1,500 m, 3,000 m, cloud, rain probability.
- Get up: repeat, look at webcams from the site.
- Take off: watch sleeves, royal clusters, other candles. The sky overcomes the prognosis.
Abstract to hang in the fridge
- Cu humis + dark base → flies.
- Congestus tight → prudence.
- Anvil → don't take off or land now.
- Lenticularis → wave, not fly without formation.
- Mammatus → mature storm, away.
- "Smiling base" → dead thermal.
- 300 m minimum below base.
- If you doubt, don't fly.