In early 2002, startling changes of colour appeared on the leaves and needles of evergreen tree species at higher altitudes. The trees formed «red belts» across the mountain slopes, several hundred meters long. The discolouration was caused by frost in the previous winter. In this paper we present the reaction of conifers to frost and look at the most important occurrences of frost in the last decades. Based on experience gained following the widespread frosts of 1986/1987, we can expect most of the damaged trees to recover over the next few years. This expectation, however, will only be fulfilled if there are no subsequent and serious bark beetle attacks. Continued surveillance of the injured forest sites is, therefore, necessary.