According to the German Weather Service (DWD), the Harz is one of the rainiest regions in Lower Saxony. Since 1931, an annual average of 745 liters more water per square meter has fallen in the low mountain range than the average for the federal state, according to the meteorologists. Especially in Braunlage, it often rains, snows or hails.
As a result, the forests in the low mountain range are sometimes better protected from forest fires than the rest of Lower Saxony. "In general, the risk of forest fires in the Harz Mountains is slightly lower than in the rest of Lower Saxony because there is more precipitation," said a DWD spokeswoman. In particularly dry years such as 2018 or 2019, however, this effect has no effect. The top layer of soil with leaves and needles is particularly decisive for forest fires. This dries out very quickly and only stores precipitation for a short time. The forest fire risk index in the region is currently between warning levels 1 to 3, with five warning levels.
In Braunlage in the Harz Mountains, where Lower Saxony's highest mountain, the Wurmberg, is also located, an average of 1236.9 liters of water per square meter fell over the long term. At the other three measuring stations in the Harz Mountains, Osterode, Seesen and Langelsheim, a little more than 800 liters per square meter mostly fell to the ground. For the state of Lower Saxony, the value is 744.6. There were hardly any clear outliers in each case.
The reason for the increased precipitation in the Harz Mountains is a damming effect, also known as the windward effect. In Central Europe, wind usually comes from the west, said the DWD spokeswoman. This air accumulates on the western and southwest flanks of the Harz and then rises upwards. The air cools down and becomes clouds or precipitation. This also leads to more rain in the Brocken region. In the eastern Harz regions, there is less cloud and precipitation due to the reverse effect, the so-called Lee effect.
The German weather service was also able to determine that it is often a few degrees cooler in the Harz Mountains than in the rest of Lower Saxony. However, this is also due to the height of the mountains. For every 100 meters of altitude, the temperature drops a good half a degree. In Braunlage, the long-term average is around 6.3 degrees, in Lower Saxony it is 9 degrees.
Climate Data Center - Long-term mean forest fire risk index NDS Soil moisture in Germany
