Criteria: how levels are computed
The exact rules the system uses, as they are in the code. If this page and the code disagree, the code wins and we fix the page.
Our own thresholds, not yet validated
The thresholds were set by the project author based on the incident review documented in the methodology. They have not been validated by a meteorologist, nor by CONAF, SENAPRED or SERNAGEOMIN. Treat them as informational. See methodology.
What each level means
- No model alert
No estimated variable exceeds the caution thresholds. In the mountains, local conditions can be worse than estimated. Models do not exceed our thresholds. This does not mean the trail is safe.
- Caution
At least one estimated variable exceeds a caution threshold. Prepare for sudden changes, check return routes and ask park rangers.
- Danger
At least one estimated variable exceeds a danger threshold. The site always shows which variable triggers it and its value. Check with CONAF before any decision.
How variables are combined
Each terrain type has a list of rules checked in a fixed order; the level is that of the first rule that matches. This almost always equals “the level of the most severe variable”, with two exceptions worth knowing:
- Volcano, May to August: a temperature below −5 °C leaves the level at Caution even if gusts exceed the Danger threshold.
- Altiplano, November to March: rain or snow above the caution threshold leave the level at Caution even if gusts exceed the Danger threshold.
We document it exactly as it is in the code; we did not change it in this review.
Which hour the estimate looks at and how often it updates
- The system queries Open-Meteo once an hour (at minute 0) for each trail.
- The level is computed from a single hour of the estimate: the current hour. It does not look at the rest of the day or the next 72 hours. Until October 2026 a time-zone bug made that hour 3 to 4 hours ahead; this is now fixed. Each page shows which hour the estimate refers to.
- The “Next 24 h” bars on each park page are context only: they are not used to compute the level.
- An alert closes when a later run no longer exceeds any threshold.
Rules by terrain type
Each trail has six base values in the database (wind, rain and snow, for caution and danger). The rules use those values, sometimes multiplied by a terrain factor. Rules apply in table order.
Trail · 55 trails
Forests, valleys, coasts and Patagonia.
| # | Level | Variable | Condition |
|---|---|---|---|
| 1 | Danger | Gusts | ≥ trail red wind |
| 2 | Danger | Sustained wind | ≥ 80% of trail red wind |
| 3 | Danger | Rain | ≥ trail red rain |
| 4 | Danger | Snow | ≥ trail red snow |
| 5 | Danger | Visibility | < 100 m (trails below 3,000 m) |
| 6 | Danger | Temperature | < −10 °C with wind > 40 km/h |
| 7 | Caution | Gusts | ≥ trail yellow wind |
| 8 | Caution | Rain | ≥ trail yellow rain |
| 9 | Caution | Visibility | < 500 m (trails below 3,000 m) |
| 10 | Caution | Temperature | < −5 °C with wind > 25 km/h |
Mountain range · 12 trails
Mountain trails (approx. 1,500–3,000 m).
| # | Level | Variable | Condition |
|---|---|---|---|
| 1 | Danger | Gusts | ≥ 75% of trail red wind |
| 2 | Danger | Sustained wind | ≥ 60% of trail red wind |
| 3 | Danger | Rain | ≥ trail red rain |
| 4 | Danger | Snow | ≥ trail red snow |
| 5 | Danger | Temperature | < −12 °C with wind > 30 km/h |
| 6 | Caution | Gusts | ≥ 75% of trail yellow wind |
| 7 | Caution | Rain | ≥ trail yellow rain |
| 8 | Caution | Snow | ≥ trail yellow snow |
| 9 | Caution | Visibility | < 500 m (trails below 3,000 m) |
| 10 | Caution | Temperature | < −6 °C with wind > 20 km/h |
Volcano · 10 trails
Volcano ascents. Modelled wind is unreliable: temperature goes first.
| # | Level | Variable | Condition |
|---|---|---|---|
| 1 | Danger | Temperature | < −10 °C (May–Aug) |
| 2 | Caution | Temperature | < −5 °C (May–Aug) |
| 3 | Danger | Temperature | < −15 °C |
| 4 | Caution | Temperature | < −8 °C |
| 5 | Danger | Rain | ≥ trail red rain |
| 6 | Caution | Rain | ≥ trail yellow rain |
| 7 | Danger | Snow | ≥ trail red snow |
| 8 | Caution | Snow | ≥ trail yellow snow |
| 9 | Danger | Gusts | ≥ 60% of trail red wind |
| 10 | Caution | Gusts | ≥ 60% of trail yellow wind |
Altiplano · 5 trails
Above 3,500 m in the north. Altiplanic winter season Nov–Mar.
| # | Level | Variable | Condition |
|---|---|---|---|
| 1 | Danger | Temperature | < −15 °C |
| 2 | Caution | Temperature | < −8 °C |
| 3 | Caution | Rain | ≥ trail yellow rain (Nov–Mar) |
| 4 | Caution | Snow | ≥ trail yellow snow (Nov–Mar) |
| 5 | Danger | Gusts | ≥ 70% of trail red wind |
| 6 | Caution | Gusts | ≥ 70% of trail yellow wind |
| 7 | Danger | Rain | ≥ trail red rain |
| 8 | Danger | Snow | ≥ trail red snow |
Variables: gusts and sustained wind at 10 m (km/h), precipitation (mm/h), snowfall (cm/h), 2 m temperature (°C) and visibility (m), for one hour. Source: src/lib/alerts.ts (evaluarRiesgo).
Effective thresholds by trail
Gust values already multiplied by their terrain factor, plus base rain and snow values. Database copy from 2026-10-07.
Show all 82 trails
| Park / trail | Terrain | Gust ▲ / ■ (km/h) | Rain ▲ / ■ (mm/h) | Snow ▲ / ■ (cm/h) |
|---|---|---|---|---|
| Lauca National Park — Bofedales Trail (4,500 m) | Altiplano | 35 / 49 | 8 / 15 | 3 / 10 |
| Lauca National Park — Lake Chungará Trail (4,520 m) | Altiplano | 35 / 49 | 8 / 15 | 3 / 10 |
| Nevado Tres Cruces National Park — Santa Rosa Lagoon Trail (4,600 m) | Altiplano | 31.5 / 45.5 | 6 / 12 | 2 / 8 |
| Los Flamencos National Reserve — Atacama Salt Flat Trail (2,300 m) | Altiplano | 38.5 / 56 | 8 / 15 | 3 / 10 |
| Los Flamencos National Reserve — Valley of the Moon Trail (2,500 m) | Altiplano | 38.5 / 56 | 8 / 15 | 3 / 10 |
| El Morado Natural Monument — El Morado Lagoon Trail (3,500 m) | Mountain range | 37.5 / 52.5 | 8 / 15 | 3 / 10 |
| Cerro Castillo National Park — Cerro Castillo Circuit (2,675 m) | Mountain range | 41.3 / 63.8 | 8 / 15 | 5 / 15 |
| Huerquehue National Park — Cerro San Sebastián Trail (1,600 m) | Mountain range | 41.3 / 63.8 | 12 / 22 | 5 / 12 |
| La Campana National Park — La Campana Summit Trail (1,910 m) | Mountain range | 41.3 / 60 | 10 / 20 | 5 / 15 |
| Laguna del Laja National Park — Waterfalls Trail (1,800 m) | Mountain range | 41.3 / 60 | 10 / 20 | 5 / 15 |
| Torres del Paine National Park — Valle del Francés (1,050 m) | Mountain range | 33.8 / 52.5 | 8 / 15 | 3 / 8 |
| Vicente Pérez Rosales National Park — Paso de las Nubes Trail (1,350 m) | Mountain range | 37.5 / 56.3 | 10 / 18 | 5 / 12 |
| Altos de Lircay National Reserve — El Enladrillado Trail (2,200 m) | Mountain range | 37.5 / 56.3 | 10 / 20 | 5 / 15 |
| Altos de Lircay National Reserve — Las Ánimas Trail (2,300 m) | Mountain range | 41.3 / 63.8 | 10 / 20 | 5 / 12 |
| Huemules de Niblinto National Reserve — Huemul Trail (1,600 m) | Mountain range | 41.3 / 60 | 10 / 20 | 5 / 15 |
| Río de Los Cipreses National Reserve — Cipreses River Trail (2,000 m) | Mountain range | 41.3 / 60 | 10 / 20 | 5 / 15 |
| Ñuble National Reserve — Achibueno Lagoon Trail (1,800 m) | Mountain range | 41.3 / 60 | 10 / 20 | 5 / 15 |
| Cerro Nielol Natural Monument — Cerro Nielol Main Trail (178 m) | Trail | 65 / 95 | 15 / 25 | 5 / 15 |
| Cueva del Milodón Natural Monument — Milodon Cave Trail (150 m) | Trail | 55 / 80 | 10 / 20 | 5 / 15 |
| Dos Lagunas Natural Monument — Two Lakes Trail (1,200 m) | Trail | 55 / 80 | 12 / 25 | 5 / 15 |
| Lahuen Ñadi Natural Monument — Alerce Forest Trail (120 m) | Trail | 60 / 90 | 15 / 30 | 5 / 15 |
| Pichasca Natural Monument — Fossils Trail (850 m) | Trail | 60 / 90 | 10 / 20 | 5 / 15 |
| Alerce Andino National Park — Chaiquenes Trail (1,500 m) | Trail | 55 / 80 | 15 / 30 | 5 / 15 |
| Alerce Costero National Park — Millenary Alerce Trail (900 m) | Trail | 60 / 85 | 15 / 30 | 5 / 15 |
| Juan Fernández National Park — Selkirk Viewpoint Trail (915 m) | Trail | 55 / 80 | 12 / 25 | 5 / 15 |
| Bernardo OHiggins National Park — Pío XI Glacier Trail (500 m) | Trail | 45 / 70 | 15 / 30 | 5 / 15 |
| Bosque Fray Jorge National Park — Relict Forest Trail (650 m) | Trail | 60 / 90 | 10 / 20 | 5 / 15 |
| Cerro Castillo National Park — Viewpoint Trail (1,500 m) | Trail | 50 / 75 | 12 / 25 | 5 / 15 |
| Chiloé National Park — Cole Cole Trail (300 m) | Trail | 60 / 90 | 15 / 30 | 5 / 15 |
| Chiloé National Park — Tepual Trail (200 m) | Trail | 60 / 90 | 15 / 30 | 5 / 15 |
| Conguillío National Park — Captren Lagoon Trail (1,200 m) | Trail | 55 / 80 | 12 / 25 | 5 / 15 |
| Conguillío National Park — Los Paraguas Trail (1,550 m) | Trail | 60 / 90 | 12 / 22 | 5 / 15 |
| Huerquehue National Park — Lake Tinquilco Trail (800 m) | Trail | 55 / 80 | 12 / 25 | 5 / 15 |
| Huerquehue National Park — Los Lagos Trail (1,400 m) | Trail | 60 / 90 | 10 / 20 | 5 / 15 |
| La Campana National Park — Andinista Trail (1,500 m) | Trail | 55 / 80 | 10 / 20 | 5 / 15 |
| Laguna San Rafael National Park — San Rafael Lagoon Trail (200 m) | Trail | 50 / 75 | 15 / 30 | 5 / 15 |
| Llanos de Challe National Park — Carrizal Beach Trail (250 m) | Trail | 60 / 90 | 10 / 20 | 5 / 15 |
| Nahuelbuta National Park — Coihue Trail (1,200 m) | Trail | 60 / 90 | 12 / 25 | 5 / 15 |
| Nahuelbuta National Park — Eagle Stone Trail (1,440 m) | Trail | 60 / 90 | 12 / 25 | 5 / 15 |
| Nonguén National Park — Native Forest Trail (350 m) | Trail | 60 / 90 | 12 / 25 | 5 / 15 |
| Pali Aike National Park — Pali Aike Crater Trail (300 m) | Trail | 55 / 80 | 10 / 20 | 5 / 15 |
| Pan de Azúcar National Park — Pan de Azúcar Island Trail (100 m) | Trail | 65 / 95 | 10 / 20 | 5 / 15 |
| Pan de Azúcar National Park — Mirador Trail (900 m) | Trail | 65 / 95 | 10 / 20 | 5 / 15 |
| Patagonia National Park - Chacabuco — Avilés Trail (1,200 m) | Trail | 50 / 75 | 12 / 25 | 5 / 15 |
| Patagonia National Park - Jeinimeni — Jeinimeni Lake Trail (900 m) | Trail | 50 / 75 | 12 / 25 | 5 / 15 |
| Patagonia National Park - Pumalín — Alerce Trail (600 m) | Trail | 55 / 80 | 15 / 30 | 5 / 15 |
| Patagonia National Park - Pumalín — Hidden Waterfalls Trail (800 m) | Trail | 55 / 80 | 15 / 30 | 5 / 15 |
| Patagonia National Park - Tamango — Huemul Trail (1,200 m) | Trail | 50 / 75 | 12 / 25 | 5 / 15 |
| Puyehue National Park — Aguas Calientes Trail (900 m) | Trail | 55 / 80 | 12 / 25 | 5 / 15 |
| Queulat National Park — Queulat River Trail (600 m) | Trail | 55 / 80 | 15 / 30 | 5 / 15 |
| Queulat National Park — Hanging Glacier Trail (700 m) | Trail | 55 / 80 | 15 / 30 | 5 / 15 |
| Radal Siete Tazas National Park — Coigue Trail (1,000 m) | Trail | 60 / 90 | 10 / 20 | 5 / 15 |
| Radal Siete Tazas National Park — Seven Tazas Trail (900 m) | Trail | 55 / 85 | 10 / 20 | 5 / 15 |
| Río Clarillo National Park — Clarillo River Trail (1,200 m) | Trail | 60 / 90 | 10 / 20 | 5 / 15 |
| Tolhuaca National Park — Malleco Lagoon Trail (1,000 m) | Trail | 55 / 80 | 12 / 25 | 5 / 15 |
| Tolhuaca National Park — Malleco Waterfall Trail (900 m) | Trail | 55 / 80 | 12 / 25 | 5 / 15 |
| Torres del Paine National Park — Base Las Torres (900 m) | Trail | 70 / 100 | 12 / 25 | 5 / 15 |
| Torres del Paine National Park — Circuit O (1,241 m) | Trail | 50 / 80 | 8 / 15 | 5 / 15 |
| Torres del Paine National Park — Grey Glacier (250 m) | Trail | 45 / 70 | 8 / 15 | 3 / 8 |
| Torres del Paine National Park — W Trek (800 m) | Trail | 60 / 90 | 10 / 20 | 5 / 15 |
| Vicente Pérez Rosales National Park — Petrohué Waterfalls Trail (600 m) | Trail | 60 / 90 | 12 / 25 | 5 / 15 |
| Coyhaique National Reserve — Green Lagoon Trail (900 m) | Trail | 55 / 80 | 12 / 25 | 5 / 15 |
| Federico Albert National Reserve — Dunes Trail (100 m) | Trail | 65 / 95 | 12 / 25 | 5 / 15 |
| Lago Peñuelas National Reserve — Lakeside Trail (380 m) | Trail | 60 / 90 | 10 / 20 | 5 / 15 |
| Laguna Parrillar National Reserve — Parrillar Lagoon Trail (450 m) | Trail | 55 / 85 | 12 / 25 | 5 / 15 |
| Laguna Torca National Reserve — Birdwatching Trail (15 m) | Trail | 60 / 90 | 12 / 25 | 5 / 15 |
| Las Chinchillas National Reserve — Wildlife Watching Trail (1,600 m) | Trail | 60 / 90 | 10 / 20 | 5 / 15 |
| Los Ruiles National Reserve — Ruiles Forest Trail (450 m) | Trail | 60 / 90 | 12 / 25 | 5 / 15 |
| Magallanes National Reserve — Magellanic Forest Trail (600 m) | Trail | 55 / 85 | 12 / 25 | 5 / 15 |
| Pampa del Tamarugal National Reserve — Geoglyphs Trail (1,050 m) | Trail | 60 / 90 | 8 / 15 | 3 / 10 |
| Río Simpson National Reserve — Simpson River Trail (400 m) | Trail | 55 / 80 | 12 / 25 | 5 / 15 |
| Valdivia National Reserve — Valdivian Forest Trail (450 m) | Trail | 60 / 90 | 15 / 30 | 5 / 15 |
| Conguillío National Park — Sierra Nevada Trail (2,554 m) | Volcano | 33 / 51 | 8 / 15 | 5 / 15 |
| Laguna del Laja National Park — Antuco Volcano Trail (2,979 m) | Volcano | 30 / 48 | 5 / 12 | 5 / 15 |
| Llullaillaco National Park — Llullaillaco Volcano Ascent (6,739 m) | Volcano | 24 / 36 | 5 / 10 | 2 / 6 |
| Puyehue National Park — Antillanca Trail (1,700 m) | Volcano | 30 / 45 | 12 / 25 | 5 / 15 |
| Vicente Pérez Rosales National Park — Osorno Volcano Trail (2,652 m) | Volcano | 27 / 39 | 10 / 20 | 3 / 10 |
| Villarrica National Park — Quetrupillán Volcano Ascent (2,360 m) | Volcano | 36 / 54 | 10 / 18 | 3 / 8 |
| Villarrica National Park — Villarrica Volcano (2,847 m) | Volcano | 24 / 42 | 5 / 10 | 5 / 15 |
| Llanquihue National Reserve — Calbuco Volcano Trail (1,200 m) | Volcano | 30 / 45 | 12 / 25 | 5 / 15 |
| Malalcahuello National Reserve — Lonquimay Volcano Trail (2,800 m) | Volcano | 27 / 39 | 10 / 20 | 3 / 10 |
| Mocho-Choshuenco National Reserve — Mocho Volcano Ascent (2,422 m) | Volcano | 27 / 39 | 10 / 20 | 3 / 10 |
Temperature and visibility rules are fixed per terrain (table above). On the altiplano, caution-level rain and snow only count from November to March.
Known limits
- Estimate point: Open-Meteo estimates for a point with its own elevation (90 m terrain model), which can be far below or above the section you are on. Each page shows that elevation next to the trail’s.
- Wind: in Patagonia and on volcanoes, models underestimated wind in the incidents we reviewed (see methodology).
- Visibility: Open-Meteo describes it as “viewing distance, influenced by low clouds, humidity and aerosols” and does not publish its accuracy. Local mountain fog may not show up. If the value is missing, the system assumes 10 km. Treat it as a weak reference.
- The model does not see ground conditions: ice, accumulated snow, crevasses, floods or rockfall.
Confidence
- Low: altiplano above 3,500 m.
- Medium: volcano above 2,000 m.
- High: everything else. “High” does not include a Patagonia adjustment, although we documented wind underestimation there; that is why we show a separate note.
- On volcano and altiplano trails three models are compared (best_match, GFS and ICON). If they differ by more than 25 km/h wind, 35 km/h gusts or 5 °C, divergence is marked high. The comparison does not change the level.
Volcanic technical alert
In parks with volcanoes we show the official technical alert from SERNAGEOMIN (RNVV) . It is independent of our weather estimates and has four levels: green, yellow, orange and red. For their meaning and current restrictions, always check SERNAGEOMIN and SENAPRED.
Data source
Open-Meteo (CC BY 4.0 licence). The level uses the “best_match” option, where Open-Meteo picks the model for each point automatically. It is queried at each trail’s start coordinate, not at on-site weather stations.
Corrections to this page
Until October 2026 this page showed a summary table that did not match the code: for example it said visibility “< 1,000 m / < 200 m” (the code uses < 500 m / < 100 m), single sustained-wind thresholds “≥ 55 / ≥ 80 km/h” (the code uses each trail’s values and has no caution rule for sustained wind) and a “20–30%” reduction for high mountains (the code applies factors of 0.75, 0.7 and 0.6 by terrain). It also attributed the values to technical references (UIAA, DMC) that are not their real source. We fixed it to match the code.
Do you know weather or mountains?
It helps if you review these thresholds or tell us when the estimate did not match what you experienced on the ground.
alertaparques@gmail.com