La Grande Sure
📍 Rhone-Alpes , Departement de l'Isere · Nearest city: Saint-Joseph-de-Riviere (4 km)
56 XC score / 100 · takeoff at 1578 m · 📍 View on map
Coordinates and external links
45.33530, 5.69649Forecast next days
Updated: 2026-04-19 16:11 UTC · Source: Open-Meteo · Thermal window 10:00–18:00 local time
Día volable, condiciones decentes, base de cúmulos ~641 m, viento 11 km/h.
base ~641m · wind 11 km/hDía volable, condiciones decentes, base de cúmulos ~829 m, viento 10 km/h.
base ~829m · wind 10 km/hCondiciones marginales, base de cúmulos ~1016 m, viento 9 km/h.
base ~1016m · wind 9 km/hComposite flyability score (CAPE + LI + wind + precip + low clouds). Cross-check with local pilots before flying.
Detailed hourly weather
2026-04-20❌ Not recommended · peak 65 at 15h
- Cobertura nubosa >85% — sin radiación para disparar
- Cloud suck alto (80/100) — base bajo freezing con CU
| 08 35 ☁️⚠️ | 09 55 ☁️⚠️ | 10 50 ☁️⚠️ | 11 40 | 12 40 | 13 50 | 14 55 | 15 65 | 16 55 | 17 55 | 18 50 | 19 50 | 20 50 |
Peak 15h: CAPE 0 J/kg · LI 0.1 · BL top 1245 m · w* 0.0 m/s · cloud base 2403 m · 0°C at 2830 m · Pro score 66/100 · sun 31° over slope
2026-04-21❌ Not recommended · peak 55 at 17h
- Día muy estable (CAPE<50, LI>2) — sin térmicas
- Cloud suck alto (65/100) — base bajo freezing con CU
| 08 30 | 09 30 | 10 30 | 11 30 | 12 30 ☁️⚠️ | 13 30 ☁️⚠️ | 14 30 ☁️⚠️ | 15 50 ☁️⚠️ | 16 50 ☁️⚠️ | 17 55 | 18 55 | 19 50 | 20 30 |
Peak 17h: CAPE 0 J/kg · LI 3.3 · BL top 1230 m · w* 0.0 m/s · cloud base 2415 m · 0°C at 2800 m · Pro score 58/100 · sun 18° over slope
Hourly flyability (0–100). ⛈️ = storm risk · ☁️⚠️ = cloud suck · 🏔️ = active ridge lift. CAPE = convective energy, LI = stability, BL top = thermal ceiling, w* = estimated dry thermal velocity. Source: Open-Meteo (ECMWF/GFS/ICON blend model).
Estimated vertical profile (Sounding)
Reference time: 15:00 (peak of the day)
Surface T: 10.6°C · Td: 4.0°C
LCL (cloud base): 825 m
BL top: 1245 m
0°C level: 2830 m
Approximate profile from surface variables + synoptic levels. Red lines = temperature, dashed blue = dew point. Orange bands = detected inversions.
Takeoff orientations
Green = good orientation · Yellow = possible · Gray = not suitable
Why this site has thermal potential
| Factor | Value | Interpretation |
|---|---|---|
| Hotspot density (5 km) | 7 | Medium |
| Avg thermal probability | 0.83 | Based on thousands of aggregated IGC flights |
| Solar orientation | 0.38 | Slope faces south in northern hemisphere |
| Own flight history | 0.00 | Thermals detected in platform IGC tracks |
Takeoff description
you can find a windsock above the chalet of Jusson. clean grass area.
Nearby sites
Le Grand Ratz (54) · Chalais (55) · Charmant Som (47) · Grand Som (50) · Saint Pierre de Chartreuse - La Scia (70) · Pravouta (72)