2024 Arctic Report Card: Big regional differences in the length of the 2023-24 snow season across the Arctic
Details
Over the 2023–2024 season, snow accumulation across the Arctic exceeded the 1991–2020 average, according to the Arctic Report Card. While some localized areas experienced snow cover duration that was relatively long compared to recent years, long-term records show on average snow is melting earlier in both North America and Eurasia.
This map shows how the length of the 2023-24 snow-covered season ranked in the historical record dating back to 1998. The lightest blue indicates places that had their longest snow-covered season in the recent (26-year) record, and dark blue indicates places that had their shortest season. Record- and near-record-short snow cover duration dominate across much of Canada. In contrast, longer snow cover duration is evident in Scandinavia, stretches of eastern Siberia, and some parts of Alaska.
The graph shows satellite-based June snow cover extent since 1967 compared to the 1991-2020 average. (The values have been standardized by scaling each year against the highest and lowest snow cover extents in the record, so they don’t have any units.) Historically, much of the Arctic remained at least partially snow covered well into the late spring, but a long-term decline is clear in both the Eurasian (dark blue line) and North American (bright blue line) sides of the Arctic. The five-year averages stayed above the 1991–2020 average until 2008. They have remained below the 1991–2020 average since. Report card authors state that, over 2009–2023, May and June melt has occurred up to two weeks earlier in both the Eurasian and North American Arctic compared to historical conditions.
Snow’s importance in the Arctic cannot be overstated. While it lasts, it reflects roughly 90 percent of the sunlight reaching it, keeping the region cool and staving off permafrost thaw. As it melts, snow affects the timing and amount of river flows, and replenishes soil moisture, thereby affecting fire risk. And when snow retreats earlier than normal, it leaves behind “mismatched” animals whose fur and feathers evolved to change with the seasons.
Read the snow essay in the 2024 Arctic Report Card for more details on the 2023-24 snow season, including additional information on the timing of the recent season’s snow melt and long-term trends in snow amount.
Reference
Mudryk, L.R., Chereque, A.E., Derksen, C., Luojus, K., Decharme, B. (2024). Terrestrial snow cover. Arctic Report Card: Update for 2024.