The soaring season in the American Southwest is a paradoxical mix of relentless sun, towering mesas, and unbelievably strong thermals. When the temperature climbs above 90 °F (32 °C) and the desert floor radiates heat, the sky above can become a playground of rising air---if you know how to read it and stay safe. Below is a practical guide for pilots looking to hone their thermalling skills in this harsh yet rewarding environment.
Understand the Local Thermal Landscape
| Region | Typical Terrain | Key Thermal Drivers |
|---|---|---|
| Arizona (Sierra Vista, Flagstaff) | High desert plateaus, pine forests at higher elevations | Solar heating of dark basalt, canyon‑rim convergences |
| New Mexico (Albuquerque, Santa Fe) | Wide mesas, riparian corridors, volcanic fields | Surface‑temperature contrast between irrigated fields and dry scrub |
| Southern California (Mojave, Sonoran) | Open playa, sparse sagebrush | Clear‑sky heating, dune‑induced wind shear |
- Surface contrast is king -- Dark rock and dry soil heat faster than vegetation or water, creating stronger updrafts.
- Topography amplifies lift -- Ridge lifts combine with thermals on the leeward side of mesas, giving a "thermal‑ridge sandwich."
- Time of day matters -- Peak thermals usually appear 2--3 hours after sunrise and linger until late afternoon, but desert storms can push the window earlier.
Pre‑Flight Planning
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Study the Forecast
- Look for high‑pressure ridges with clear skies and light winds (< 8 kt).
- Spot any expected afternoon thunderstorm activity; avoid days with strong convergence zones.
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Check Day‑time Temperature Trends
- Use a ground‑temperature map (NOAA's METAR data) to identify the hottest surfaces.
- Expect surface temperatures 10‑15 °F (5‑8 °C) above the ambient air → stronger thermals.
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Select Launch Sites Wisely
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- Sun protection : UV‑blocking sunglasses, sunscreen, a lightweight hat.
- Hydration : Minimum 1 L of water per hour of flight; carry a sealed bottle in a padded cockpit pocket.
- Thermal‑sensing gear : An infrared thermometer or a handheld temperature probe can help you verify ground‑heat patterns before launch.
Reading the Sky -- Visual Cues
| Cue | What It Means | How to Exploit |
|---|---|---|
| Cumulus "mushrooms" | Growing cloud tops indicate strong updrafts beneath. | Circle the base; look for a "hole" in the cloud that often marks the strongest lift. |
| Dust devils or sand whirls | Small, rotating columns of hot air. | Fly near the base; the surrounding inflow can boost climb rates. |
| Bird activity | Hawks, training eagles, and swallows will ride thermals. | Follow their flight paths; they often locate the best lift. |
| Shimmering heat waves | Mirages over hot surfaces. | Use them as a rough estimate of surface heating intensity. |
| Differential vegetation color | Darker patches = hotter ground. | Position yourself over these patches for stronger thermals. |
Tip: In the Southwest, thermals can be "narrow" because of the fragmented terrain. Keep your bank angle moderate (15‑30°) to conserve altitude while staying inside the lift core.
Core Thermalling Techniques
4.1. Entry -- "Finding the Core"
- Approach low and fast to preserve altitude while you search.
- Spot the lift by watching your variometer for a subtle rise (+0.5 m/s).
- Turn gently (30° bank) and maintain a moderate airspeed (≈ 70 % of your best glide speed).
4.2. Circling -- "The Perfect Spiral"
- Radius : Aim for 150‑200 ft (45‑60 m) in the Southwest; tighter circles can cause you to slip out of the thermal due to turbulence.
- Bank angle : 20‑30° gives a good balance of lift and turn rate without over‑loading the wing.
- Airspeed control : Keep a slight excess of speed (≈ 5 kt above stall) to stay out of the turbulent core while still extracting lift.
- Variometer monitoring : Adjust bank and pitch to keep the climb rate above 1 m/s. If the variometer drops, widen the turn or slide a bit outward.
4.3. "Dive‑and‑Climb" for Strong but Thin Thermals
When you encounter an intense but narrow thermal (common over basalt outcrops):
- Dive slightly (pitch down 5‑10°) to gain speed.
- Dive through the core to locate the maximum lift spot.
- Pull up sharply into a tighter circle while maintaining the same bank.
- Repeat every few seconds to stay within the hottest column.
4.4. Transitioning Between Thermals
- Glide to the next lift on the lee side of ridges or along valleys where converging breezes form new thermals.
- Use "blue‑sky searching" : Look for clear patches of sky that contrast with a sea of cumuli---those gaps often hide the next thermal source.
Managing Heat and Fatigue
- Hydration cadence : Sip water every 15 minutes; dehydration impairs judgment and reduces reaction time.
- Skin protection : Reapply sunscreen every 2 hours, even under the cockpit canopy.
- Mental breaks : After a strong climb (≥ 1500 ft), take a brief glide‑out to review your route and let your body cool.
- Clothing : Wear breathable, moisture‑wicking layers; avoid cotton that traps heat.
Safety Checklist for Southwest Summer Thermalling
| Item | Why It Matters | Quick Test |
|---|---|---|
| Pre‑flight weather briefing | Avoid unexpected storms. | Verify no thunderstorm watch within 50 nm. |
| Backup navigation | GPS can be unreliable over canyons. | Keep a paper map and compass handy. |
| Altitude awareness | High terrain + hot air = density altitude spikes. | Continuously compare GPS altitude with terrain elevation. |
| Emergency water supply | Desert crashes can leave you stranded. | Carry at least 2 L in a sealed container. |
| Communication plan | Remote launch fields may have limited coverage. | File a flight plan and check‑in at 30‑minute intervals. |
Putting It All Together -- A Sample Flight Profile
- 06:30 -- Arrive at a desert airstrip near Sedona; check METAR (clear, 78 °F, winds 5 kt from the west).
- 07:00 -- Launch, head toward the red‑rock mesa. Observe a line of cumuli forming over the north‑facing basalt outcrops.
- 07:15 -- Enter first thermal, radius 180 ft, bank 25°, climb 1.2 m/s → gain 800 ft.
- 07:30 -- Glide westward, sight a dust devil over a dry wash; dive‑and‑climb to capture a narrow but powerful lift (2 m/s).
- 08:00 -- Cross a ridge; use ridge lift to transition to a second thermal over a pine‑forest edge.
- 08:45 -- Begin descent, monitor temperature drop, and plan landing at the original field.
- 09:00 -- Land, log flight data, debrief: strongest thermals were over basalt; dust devils added 300 ft of altitude that day.
Final Thoughts
Mastering thermalling in the scorching Southwest isn't just about chasing the strongest lift; it's about reading the land , respecting the heat , and adapting your technique to fragmented, high‑altitude updrafts. By combining thorough pre‑flight planning, keen visual observation, disciplined circling tactics, and diligent safety habits, you'll turn the summer desert sky from a hostile furnace into a boundless arena of effortless soaring.
Happy soaring---may every thermal you find lift you higher than the next!