Forecasters are predicting an 85% chance that La Niña could last through the winter and a 60% chance it could last through spring of 2021. This weather phenomenon is something that could contribute to increased chances of flooding.
La Niña occurs when the tropical ocean waters near the equator of South America are colder as a result of stronger than normal trade winds pushing the warm water west towards Asia. The cold waters from the deeper parts of the ocean flow upward and the jet stream moves further north than its normal path. When this happens, usually the Pacific Northwest part of the country gets heavier than normal precipitation that often leads to flooding.
Typically during a La Niña year, the Pacific Northwest gets hit with higher than normal precipitation. This increased wet weather may bring about flooding from La Niña’s increased rainfall. Heavier snows may also increase flood risk during spring snow melt.
The Midwest may also be at an increased risk of flooding during a La Niña year since it’s anticipated to bring about more rain and snowfall in certain parts of the Midwest.
With La Niña, the Southwest often is dry. This is not a good combination in our already drought and fire-ridden locations. This could perpetuate even greater drought-like conditions that could blow up the 2021 fire season.