How to detect freezing rain and freezing drizzle
Freezing precipitation is a very dangerous weather situation. It can cause major accidents, especially in traffic. So it is important to know about it. A disdrometer cannot detect freezing rain as it is still rain what passes the detecting area of the device.
There are devices available in the market to detect freezing precipitation. They consist of an oscillating rod that is exposed to the weather. If the rain freezes on the surface of the rod, the frequency changes. That change is detected. When the measuring time has passed a heater removes the ice from the rod, and the measuring cycle starts all again.
Such devices are very expensive, and even the governmental weather services do not generally use them.
The means to detect freezing precipitation is to put the readings of different observation types together to get an estimate if the rain is freezing or not.
- Wikimedia Commons: Traffic sign Schleudergefahr
