U.S. climate article predicts snow deficit for Maritimes for upcoming El Nino winter

Snow-covered trees in Cornwall, P.E.I., after the area's first five-plus cm of snowfall of the year. (Courtesy: Chris Marshall)

A new article from the climate branch of the National Oceanographic and Atmospheric Administration of the U.S. government correlates El Nino winters to below average snowfall for the Maritimes.

The data set depicts snow in the Maritimes falling a few to more than 10 cm below 30-year averages during observed El Nino winters between 1959 and 2023. The 30-year average for snow was taken as the period from 1991 to 2020. Winter was defined as the months of January through March.

The greatest deficit for snow in the Maritimes was indicated to be in Nova Scotia, eastern New Brunswick, and Prince Edward Island.

The article also includes a second map showing a more evenly spread deficit of snow in the region during moderate-to-strong El Nino winters.

The author, Michelle L’Heureux, and reviewer of the post, NWS Climate Service Program Manage Brian Brettschneider, are careful to note that the maps just depict averages. By the nature of being averages, there would certainly have been some winters during El Nino years that had above or significantly above normal snowfalls. A third data map indicates that about six to 10 of the last 13 El Nino winters in the Maritimes have been associated with below average snowfall in the Maritimes.

El Nino is a phase of water temperatures in the Pacific Ocean in which the surface waters are found to be warmer in an area extending from the centre-equatorial area of the Pacific to near the coastline of South America. We are in the El Nino phase now and it is predicted to be a strong El Nino winter.

The maps and findings were found through the use of the ECMWF ERA5 reanalysis dataset. That is a global climate reanalysis created by combining real world observations of the weather and climate along with computer modelling of the atmosphere.