(COLORADO) — A major weather pattern will affect how much snowfall the Western U.S. will receive this ski season. As winter approaches, those who partake in skiing and other winter sports may want to double-check the weather before heading out. The El Niño-Southern Oscillation (ENSO) contains El Niño and La Niña, which impact global climate. Both affect summer and winter seasons, although the NOAA says their strongest influence occurs during the winter, which can impact snowfall and temperatures. However, La Niña seasons can cause above-average hurricane activity in the Atlantic, and below-average in the East Pacific. According to the National Oceanic and Atmospheric Administration (NOAA), El Niño causes temperatures above normal in the eastern Pacific Ocean. While La Niña means sea surface temperatures are above normal in parts around the equator. El Niño and La Niña do not occur every year, the NOAA says they typically happen every two to seven years. This year, the NOAA predicts La Niña will return for the winter season, with a 71% chance of the weather pattern emerging from September through November. In the past three seasons, the U.S. has experienced La Niña. If the weather phenomenon were to develop, this would mark the fourth La Niña season in five years. La Niña can have the strongest influence during winter, so what does that mean for Colorado and its ski season? Due to the phenomena taking place, meteorologists can often provide a more confident seasonal forecast by looking at past La Niña seasons. During the 2022-2023 ski season, a La Niña season, many resorts in the West — particularly in California and Utah — broke snowfall records. “La Niña tends to organize the wintertime jet stream in a way that favors the Pacific Northwest and Northern Tier of states with the most consistent winter snowfall,” writes OnTheSnow meteorologist Chris Tomer.“La Niña tends to leave California and the Southern Tier of states drier and warmer than normal.” This pattern isn’t conducive to atmospheric river setups, and drought can deepen as a result. In Colorado, the NOAA predicts places like Steamboat Springs and Vail may receive above-average winter conditions, while eastern cities such as Denver and Monarch are expected to stay in the normal range and southern cities like Wolf Creek will have below-average winter conditions. La Niña is expected to persist through January-March 2025. The NOAA has predicted this year's La Niña event could be weak and short in duration.