Frost in times of climate change
Spring is gradually arriving in the vineyards of Valais. An increasing issue at this time of year is the risk of frost damage. In this video, you will find a brief insight into the different types of frost, their causes and what is being done to combat the risk of frost in the vineyards of Valais.
Winter frost can occur in the Rhone Valley between December and February. At very low temperatures of -20 degrees and colder, ice forms in the vine, causing the vine to split and die. Thanks to the very mild winter, there was no danger of winter frost this year.
The second known frost start is spring frost, which can severely affect and damage young shoots. There are two different causes. Wind frost occurs when cool winds from the north sweep through the Rhone Valley, exposing the vines to sub-zero temperatures. A second cause can arise due to an inverse weather situation . When the sky opens up, warm air rises from the ground and cold air sinks – this process increases the risk of ground frost. While winegrowers are largely helpless in the face of wind frost, in an inverse weather situation it is possible to achieve air mixing on the ground using fans or candles.
Climate change is also having an increasing impact on the risk of frost in spring. Warmer temperatures mean that budding takes place two to three weeks earlier than was the case 30 years ago – which naturally increases the time span in which frost damage can occur.