South America Snow Forecast: Up to 150 cm through Thursday

Snowfall forecast map — Credit: NOAA/NCEP GFS

The South America snow forecast stays active as an ongoing storm reloads the Central Andes and expands across the south-central Andes and northern Patagonia. Confidence is strongest from Saturday afternoon, July 18, through Thursday morning, July 23. During that period, Nevados de Chillán leads with 102-152 cm, Portillo follows with 96-137 cm, and Valle Nevado reaches 90-130 cm. Many resorts have limited terrain open, while Portillo’s slopes remain closed for storm safety, so the new snow should improve coverage but may not translate immediately into full operations.

The ongoing Central Andes storm keeps cycling through Sunday, reloads most strongly Monday into Tuesday, and tapers Wednesday. The models converge on that timing and on snow levels staying between 900 and 2,100 meters, safely below the main resort bases, but they diverge on intensity at Las Leñas and on exposed-ridge wind. SLRs of 13-17:1 favor moderate to light snow, with the driest texture around Valle Nevado. Most lower-mountain wind looks manageable, though some guidance brings 40-65 km/h gusts to upper terrain, enough for intermittent lift effects during heavier snow.

Farther south, ongoing snow at Nevados de Chillán and Corralco eases Sunday before a stronger reload Tuesday and Wednesday, while snow develops across Chapelco and Cerro Catedral. The models converge on the broad timing and on snow levels near 1,000-1,700 meters, but they diverge considerably on intensity and wind impacts. SLRs mostly run 8-12:1, pointing to dense or moderate snow, especially near the lower slopes. Upper-mountain gusts could reach 50-80 km/h. Cerro Castor stays colder with snow levels near sea level, but its lighter pulses add only 7-10 cm through Thursday morning.

From Thursday afternoon through Saturday, another warmer wave is likely, but forecast detail becomes much less dependable. The models loosely converge on the timing, then diverge sharply on intensity, snow levels, and wind, with snow levels potentially rising into the 1,800-3,000-meter range. A conservative model-based estimate is another 20-60 cm across favored high terrain, with denser snow and a risk of wet lower slopes. Late Sunday through Tuesday may bring an additional 30-80 cm to parts of the south-central Andes, while one drier solution leaves the Central Andes with much less and wind forecasts remain highly variable.