Everything is in place for a massive storm cycle to slam Chile and Argentina over the next week. Stubborn, strong high-pressure systems on both sides of the continent will allow a series of low-pressure systems to move through the Andes with a consistent subtropical moisture tap and a few shots of cold air. With all the major players in place, it’s time to get into some of the details. 

There is no doubt this storm cycle will deliver big, big totals across the resorts through the middle of next week, but there are some key factors to keep in mind. First, the storm will arrive in two waves, the second of which will be more substantial and prolonged. The first wave will bring snow from Wednesday night through Saturday morning, while the second will unload on the region from Saturday night through Wednesday. Both waves have the potential for some periods of very intense snowfall. A longer stretch of high snowfall rates is expected with the second wave.

Strong to extreme winds will also be a concern with these storms, and they will be more impactful during the second wave. The heaviest winds from the first wave will impact the central and northern zones with gusts in the 40 to 80 km/hr range.

During the second phase of this cycle, the strongest winds will hit the central zone, with gusts ranging from 50 to 100 km/hr from Saturday through Monday, and likely exceeding 100 km/hr in some locations on Saturday. The worst of the winds should stay south of the northern zone during this part of the storm, but it will still be gusty. 

The winds will primarily come from the northwest, given the locations of the offshore high and low pressure systems. This wind direction is less favorable for orographic precipitation to spill over onto the leeward side of the Andes. Snow totals may come in on the low end of the range for Argentinean resorts, especially south of Caviahue. 

Finally, the cold front will move into the region with more of a west/southwest to east/northeast trajectory, compared to the more common south/southwest to north/northeast. This will bring colder air farther north and allow the northern zone, with its higher elevations, to receive considerably better-quality snow. 

Let's take a look at some snow forecasts. First, the snow totals for the first wave through Saturday is shown below. You can see the first wave favoring the northern zone and the northern part of the central zone.

Next is the snow forecast for the second phase of the storm, from Saturday night through Tuesday night. You can see that during this phase of the storm, the totals on the eastern/Argentinian side of the Andes drop off significantly south of Caviahue.

And finally, here is the storm total forecast from the European model.

The Chilean resorts in the central and northern zones (Portillo, Valle Nevado, El Colorado, Antuco, Corralco, Pucon, Las Araucarias, Antillanca) are expected to receive 1 to 2 meters, with higher amounts possible around Nevados de Chillan. Las Lenas and Caviahue should also fall within this range. The rest of the Argentinian resorts (Cerro Catedral, Cerro Bayo, Chapelco) should see solid totals in the 40 to 80 cm range.

After the second storm, a fast-moving third storm is expected to move through the central and southern zones from Wednesday into Thursday, followed by another stronger storm possible next weekend. The forecast is looking good!

Next update on Friday.

Thanks for reading the South America Daily Snow!

Luke Stone
Forecaster, OpenSnow

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