When is the ground first covered with snow and when is it permanent?
In Finland the first snow cover is consired to have happened on the day when there is measurable snow in the morning observation (06 UTC). The permanent snow cover is defined as the longest period with consecutive snow cover days.
The very first snowflakes fall to the ground in late August or early September over the higher peaks in Lapland. The first ground-covering snow and permanent snow cover arrive at different times in different parts of the country. In Lapland the winter is long (approximately seven months) and the permanent snow cover comes significantly earlier than in southern Finland.
The snow cover is usually thickest in mid March, in Lapland often as late as early April. Soon after that the snow cover starts to melt fast.
|Average date of first snow cover (1981-2010 normal period)||Average starting date of permanent snow cover (1981-2010 normal period)||Average ending date of permanent snow cover (1981-2010 normal period)|
The map on the left depicts the average date of the first snow cover based on the 1981-2010 normal period. The maps in the middle and on the right depict the average beginning and ending date of the permanent snow cover based on the 1981-2010 normal period.
Maximum snow depth and the number of snow cover days
The maximum snow depth is usually found around March (most of the country) or early April (Lapland). Typically the ground is covered with snow over half a year in Lapland.
|Average snow depth (cm) on March 15th (1981-2010 normal period)||Average snow depth (cm) on March 31st (1981-2010 normal period)||Average number of days with snow cover (1981-2010 normal period)|
Average snow depth on March 15th and March 31st as well as average number of snow cover days (1981-2010 normal period).