Sometimes in March and April, showers with wintry load may enter the Low Countries from the N to NW. The upper air is very cold: at 850 hPa usually less than -5°C and at 500 hPa usually less than -30°C. This may result in heavy showers with rain, sleet, snow, small hail and accompanied by a rumble of thunder. When this precipitation falls at night it is mostly under the form of snow, in areas affected by "a street of wintry showers", snow accumulation can be quite significant. After a winter season with very mild temperatures, some of the early flowers or blossoms may already have appeared, giving a rather strange effect of Spring and Winter in one view.  

In this case blossoms of the "Forsythia", which appear in March - April, were surprised by a late cover of fresh snow.