Late-September Andes System

1. Day 9·Sep 20·Likely·134cmLanded

   The window opened today: 133.6cm for Nevados de Chillán 2026-09-22 to 2026-09-27

   The window opened today with final predictions of 133.6cm for Nevados de Chillán, 126.7cm for Corralco, and lower totals for Cerro Catedral, Cerro Perito Moreno, and Batea Mahuida. Since day 1, the top total has decreased by 14cm, and the window start has shifted one day later. Confidence remains likely, with trends on track for the two leading resorts. We continue to monitor the situation closely, especially for the resorts with lower totals where confidence is categorized as watching.

   Window Sep 22–27 · Nevados de Chillán

2. Day 8·Sep 19·Likely·134cm(-14)

   Confidence holds: 133.6cm for Nevados de Chillán 2026-09-22 to 2026-09-27

   Day 8: the window has slid a day later, and totals have adjusted accordingly. We now expect 133.6cm for Nevados de Chillán and 126.7cm for Corralco over the window from 2026-09-22 to 2026-09-27. Both resorts show likely confidence, with the biggest day expected on 2026-09-24 at 62.3cm for Nevados de Chillán and 43.2cm for Corralco. Cerro Catedral and Cerro Perito Moreno are still under observation, with totals of 53.8cm and 53.6cm respectively, while Batea Mahuida is projected to receive 34.1cm. We will continue to monitor the trends as the window approaches.

   Window Sep 22–27 · Nevados de Chillán

3. Day 7·Sep 18·Likely·148cm(-50)

   Confidence holds: 147.6cm for Corralco 2026-09-21 to 2026-09-27

   Day 7: the window start moved one day later, and totals are down 49.8cm at the top. The current prediction for the window from 2026-09-21 to 2026-09-27 shows Corralco leading with 147.6cm, followed by Nevados de Chillán at 112.8cm. Other resorts like Las Araucarias and Cerro Catedral are also expected to see significant totals, but with lower maximums. We will continue to monitor trends closely, especially at Batea Mahuida, where confidence is still being assessed.

   Window Sep 21–27 · Corralco

4. Day 6·Sep 17·Likely·197cm(-1)

   Confidence holds: 197.4cm for Nevados de Chillán 2026-09-20 to 2026-09-27

   Day 6: the window has shifted one day later, but totals remain stable with a slight decrease at the top. The current prediction for the window from 2026-09-20 to 2026-09-27 shows Nevados de Chillán leading with 197.4cm, followed by Corralco at 178.2cm. Other resorts like Volcán Osorno and Portillo are also expected to see significant snowfall, with totals of 102.7cm and 76.1cm respectively. We will continue to monitor the trends closely, especially for resorts like Cerro Perito Moreno and Las Leñas, where confidence is watching and trends are weakening.

   Window Sep 20–27 · Nevados de Chillán

5. Day 5·Sep 16·Likely·198cm(+16)

   Confidence builds: 198.2cm for Nevados de Chillán 2026-09-19 to 2026-09-26

   Day 5: the window has slid a day later, and totals are up 16.4cm at Nevados de Chillán since our last update. We expect snowfall from September 19 to September 26, with Nevados de Chillán leading the forecast at 198.2cm, followed by Corralco at 168.2cm. Other resorts show promising totals, with Batea Mahuida at 98.5cm and Volcán Osorno at 85.9cm. While confidence is likely at 12 of 15 resorts, we are watching the trends closely, particularly at Batea Mahuida and Cerro Catedral, which are strengthening but still uncertain.

   Window Sep 19–26 · Nevados de Chillán

6. Day 4·Sep 15·Watching·182cm(+92)

   Confidence builds: 181.8cm for Nevados de Chillán 2026-09-18 to 2026-09-26

   Day 4: totals up 92.1cm since the previous entry and the window held. Our current prediction for the event window from 2026-09-18 to 2026-09-26 shows Nevados de Chillán leading with 181.8cm, followed by Corralco at 152.9cm and Volcán Osorno at 108.3cm. Confidence remains watching across the board, with trends varying among resorts. Notably, Volcán Osorno and Batea Mahuida show strengthening trends, while Las Araucarias and others are experiencing weakening or delayed trends. We will continue to monitor these developments closely as we approach the event window.

   Window Sep 18–26 · Nevados de Chillán

7. Day 3·Sep 14·Watching·90cmFirst prediction

   Confidence builds: 89.7cm for Portillo 2026-09-18 to 2026-09-25

   The prediction for the upcoming mid-September Andes system indicates a total of 89.7cm for Portillo, with a range of 22–178.6cm. This pattern suggests a favorable setup for snow accumulation across the region. Portillo is likely to see the most significant totals, while Cerro Catedral, Nevados de Chillán, and Corralco are also positioned to benefit, albeit with lower expected amounts of 52.1cm, 47cm, and 47cm respectively. Resorts like Cerro Perito Moreno and Penitentes may see totals around 46.4cm and 39.8cm, while La Parva and Las Araucarias are expected to receive 33.8cm and 32.8cm. A shift in the storm's trajectory or intensity could alter these predictions significantly.

   Window Sep 18–25 · Portillo

snowrain low, snow highraindryThe dots are the freeze line — the height where rain turns to snow. Solid: straight from the models. Hollow: estimated from temperature. Above the summit line it rains on the whole mountain; below the base line it snows all the way down. Blue bars are snow in cm, amber bars rain in mm; the totals above are their sums.

Enlarge rain / snow line

• Las Araucariasbiggest day 41cm on 23 Sep · on trackPredicted56cm0–172cm, models far apart
• Volcán Osornobiggest day 16cm on 22 Sep · on trackPredicted24cm5–73cm, models far apart
• Antucobiggest day 11cm on 24 Sep · newPredicted15cm0–46cm, models far apart