A fascinating research project, led by Flemish and Dutch “cold hunters” Karel Holvoet and Pieter Bliek, is shedding light on the unique microclimates found in deep dune valleys along the Dutch and Belgian coasts

The duo has strategically placed dozens of protective covers, equipped with digital temperature gauges, in these valleys to monitor temperature fluctuations. Their project was initiated after they documented a record-breaking summer night’s frost in a Dutch dune valley last year.

Karel Holvoet, the Belgian pioneer of this research, began his studies more than a decade ago, focusing on sinkholes in the Belgian Ardennes. Sinkholes, bowl-shaped depressions common in limestone landscapes, exhibit unique cooling properties due to cold air sinking into the depression. Inspired by his findings, Karel expanded his investigations to Dutch dune valleys, which have shallower depths but exhibit similar microclimate characteristics.

To monitor temperature variations accurately, the researchers employ a network of weather stations placed in dune valleys along the Belgian and Dutch coasts. These stations are equipped with protective covers from TFA Dostmann, designed to shelter the digital temperature gauges. By placing the sensors at a height of 10 centimetres, the ‘cold hunters’ can obtain precise readings that reflect the microclimate conditions.

The data collected from more than 30 dune valleys are analysed periodically, allowing the researchers to publish scientific publications about the temperature profiles within these microclimates. In a recent breakthrough, the team recorded the coldest temperature ever registered in the Netherlands during the summer months: a freezing -0.46 °C in Camperduin’s deep dune valley on August 7, 2022.

The success of their research can be attributed, in part, to the effectiveness of the protective covers provided by TFA Dostmann. These covers are carefully designed to shield the sensors while allowing easy access for data retrieval and replacement.