Heavy precipitation (rain, hail, snow/ice)
Please note that the information on risk assessment and data is currently being developed with leading experts and be available soon.
The Netherlands has a temperate maritime climate, with precipitation occurring year-round in the form of rain, hail, and snow/ice. In this section, the definitions of hail, snow and ice are provided.
Hail
The Royal Netherlands Meteorological Institute (KNMI) defined hailstones as hard lumps of ice. These lumps are formed in clouds in which strong air currents move up and down. Roughly speaking, two types of hail can be identified:
- Hard hail are hailstones that are solid and typically formed in strong showers during summer. Large hard hailstones in particular can cause extensive damage.
- Granular hail or grauper hail are typically formed in cold-weather showers during winter. These hailstones often contain a relatively large amount of air, limiting the damaging factor. They are often smaller in size than summer hailstones.
Snow and ice
In the Netherlands, both dry and wet snowfall occur. If snowflakes encounter temperatures above zero degrees Celsius at several hundred meters in altitude, they begin to partially melt, resulting in the formation of "wet" snow. If the temperature stays below 0 °C for the entire descent, “dry” snow forms. KNMI defines a frost day as a day in which the minimum temperature is below 0°C. When the maximum temperature remains below 0 °C throughout the day, it is called an ice day. In the Netherlands, ice days occur most winters, though winters without them are happening more often.
