You don’t have to go too far back in time to find the latest example of a La Nina Winter.

The year was 2022-2023, and the long-range forecast was calling for an above-average snowfall in the northern and central Rockies, and the Sierras. How accurate was that forecast? Let’s just say the snowfall did not disappoint. That winter was epic, with record-breaking snow totals. Some ski resorts remained open for business well into June, and in some cases, July.

Yes, you read that correctly. You could still ski in July.

That winter was what they call a “triple-dip” La Nina winter—or the third consecutive La Nina winter. And this winter’s forecast is calling for another La Nina.

What, exactly, is a La Nina and how does it affect winter weather out West?

A La Nina pattern is an expansive cooling event in which the eastern Pacific sea surface temperatures are cooler and the trade winds stronger. This results in warmer and drier winters in the southern regions of the West and cooler and wetter winters in the northern Rockies and Sierras.

While this winter won’t be a triple-dip La Nina, it will almost certainly fall into a La Nina pattern sometime in the late Fall. This means destinations like Sun Valley, Idaho; Park City, Utah; Whitefish and Big Sky, Montana; and Lake Tahoe and Mammoth Lakes, California, can reasonably expect higher-than-average snowfall for the coming winter.