How does melting snow in the Alps affect the Danube River's water level?

The melting of snow and ice in the Alps plays a significant role in the hydrology of the Danube River, particularly in its upper course.

In the upper Danube, the river's water level and runoff reach their annual maximum in June, which corresponds to the period when the melting of snow and ice in the Alps is most intensive. This seasonal influx of meltwater is a primary driver of the river's flow regime in this section.1

The influence of these Alpine waters extends into the middle basin, where a distinct runoff peak occurs in June, reaching its maximum approximately 10 to 15 days after the peak in the upper course. Because the summer waters in the upper Danube are derived from this Alpine snow and glacier melt, the water temperature in that section remains low during the summer months. By the time the river reaches the lower basin, however, these Alpine characteristics disappear from the river's regime.1