Ice rain is precipitation consisting of very cool rain drops that cool down to temperatures below freezing while they fall through the layers of air. Due to the lack of seed crystals which are required to become ice, however, they do not turn to ice. Black ice only occurs during winter in our regions. Frequently precipitation is mixed and in  addition to the fluid rain drops it also contains frozen ice kernels. With what technology has to offer today, these kinds of weather conditions can be predicted with a high amount of probability. Therefore, whenever possible, one can make arrangements and respond, avoiding sidewalks and streets. Frequently it takes only a few hours for traffic to normalize and stabilize.

When very cool rain hits the ground it freezes immediately, even if the ground temperature is still higher than 0° C. And because rain is heavy and ice cannot drain off like water, a layer is formed quickly that can be several centimetres thick. The ice rain makes sidewalks and streets precipitously slippery. The layer of ice can remain for quite some time, depending on the temperature of the environment. It can take quite some time for it to melt even when the temperatures are higher than 0° C. It gets really tricky when the ice melts and a thin film of water forms on the surface of the ice because it then can become even slipperier. Extreme caution is advised during ice rain, even when temperatures are above 0°.

Small bits of ice which are difficult to distinguish from a wet street can continue to cause slippery conditions for hours after the precipitation. Furthermore, the work clearing crews can do is limited during ice rain. When the first accidents commence, and the street is blocked by vehicles, it gets difficult for them to clear the streets after the precipitation. That is why it is better to stay inside and not go out during ice rain if it can be arranged.
Level streets and side walks are not the only places that are slippery during ice rain. Bumpy surfaces and even lawns can become dangerously slick during ice rain that lasts for a longer period of time.

Likewise, train traffic and air travel can become impeded during ice rain. Expect considerable delays. Landing strips for planes are not  the only places that can be impacted by ice rain. In order to exclude all danger it will become unavoidable to cancel flights and to redirect flights to other airports where the planes can land safely.