Climate indicator - Snow

It is possible to observe changes in the snow cover in different ways, for example the greatest snow depth in winter and the duration of the snow cover. Regarding the winter's greatest snow depth, it is difficult to see a clear change over time. For northern Norrland, this also applies to the number of days with snow cover. In southern Sweden, however, the number of days with snow cover has decreased.

Comment on the results

Greatest snow depth

Thus far, there is no clear trend of decreasing snow depth in the diagrams, something that might be expected.

The snowiest winter in Sweden as a whole was 1965/66, when the average value of the winter's greatest snow depth, measured from the 43 stations, was 86 centimeters. Other winters with a lot of snow were 1976/77, 2009/10 and 2010/11.

In northern Norrland, the winter of 1905/06 was the snowiest, but there have also been snowy winters in later years. Winters with lesser amounts of snow occurred around 1930 and during the winter 1953/54.

In southern Norrland the winter of 1956/55 is the snowiest, followed by 1987/88 and 2017/18.

In Svealand it was the winter of 1965/66 which had the greatest snow depth. The depth averaged 82centimeters at most. The winter with the least snow was 2019/20, when the depth was only 16 cm. Other years with little snow is for example around 1930, in the beginning of the 70s, around 1990 and 2011/12. In contrast to Norrland, the values in Svealand are lower in recent decades.

In Götaland, some years stand out a little extra either with high snow depths or with low ones. During the winter of 2009/10, the average value of the greatest snow depth in that part of the country is greatest, 59 centimeters as an average for the 15 stations. The winter with least snow was 2019/20. In the charts we see that from about 1990 the maximum snow depth is at a lower level than before.

Days with snow cover

For Sweden as a whole, a decreasing trend of days with snow coverage is noticeable.

In northern Norrland, the snow season 1968/69 was the longest, and the season 1953/54 was the shortest. The snow season 2019/20 was the longest for that area in nearly 25 years. Since the turn of the millennium, there are only two winters that have had a longer snow season than the period of reference 1961-1990.

In southern Norrland we can see that the snow seasons 2013/14, 2014/15 and 2015/16 have been the shortest during the period. The longest season was during the winter of 1980/81. Since the winter 1990/2000, there is only one snow season longer than the period of reference 1961-1990. The length of the snow seasons has decreased since the 1980s.

In Svealand the shortest snow season studied during the period is 20019/20. Some seasons in the mid-70s and around 1990 were also relatively short. The longest snow season in Svealand and Götaland was the winter of 1969/70. Since the mid-80s the length of the snow seasons have decreased.

In Götaland, the amount of days with snow coverage varies a lot from winter to winter. Some winters the snow season is very short, such as during 2019/20 and around 1990, with only 1-3 weeks in average measured for the 12 stations in Götaland. Other winters, there has been snow coverage for over 3 months. The absolute longest snow season was 1969/70. Since the mid-80s the length of the snow seasons have been on a much lower level than previous years.

How is the winter’s greatest snow depth and days with snow cover defined?

The winter’s greatest snow depth is quite simply the greatest snow depth that has been observed during one or more days during the snow season. The season usually stretches from early autumn to late spring.

Days with snow coverage is defined as the number of days the ground has been at least half covered with snow.

Why is this indicator important?

Many winter industries are depended on snow and are kept back if the snow cover is too thin and sporadic. The snow also fulfills an important function in nature and is part of the annual cycle. A lack of snow can affect both plant life and animal life. For example, reindeer nutrition can be greatly affected. Another example is that "Vasaloppet" was canceled in 1932 and 1990 due to the lack of snow.

Large amounts of snow increase the need for snow removal and affect costs in connection with transport and also increase the risk of laces falling from roofs. Buildings can also be affected by excessive weights from snow loads on roofs.

How has the indicator been calculated?

A compilation of snow depth data during the period 1904/05 – 2020/21 has been made for all SMHI stations. However, it was found that only a limited number of stations were complete with snow depth observations each winter or could be made into complete series.

To complete the series, a number of nearby stations have been connected, for example the measurements were made in Gäddede up to 2007/08, but after that data from Frostviken has been used. For some stations and winters, data has been missing, and values ​​have been interpolated in these cases.

Since the season of 1904/05, 43 stations have been used for measurements of the winter's greatest snow depth. Since 1949/50, 37 stations have been used to measure number of days with snow. 

Future snow conditions

In a warmer climate, precipitation is expected to increase on average. At the same time, higher temperatures lead to a larger proportion of precipitation falling as rain, and snow on the ground will melt. Therefore, both the number of days with snow and maximum snow depth are generally expected to decrease.

Higher temperatures over the North Atlantic and a shorter season with sea ice over, for example, the Baltic Sea can contribute to more moisture over Sweden in winter. Therefore, there will also be heavy snowfalls in warmer climates and occasionally great snow depths.

Read more about the future climate