A dump of snow in Tignes as it warms up mid-May has brought with it a bizarre weather event known as Thundersnow.
Thunder and lightening accompanied today’s unexpected dump, causing electricity to flicker and cut out in some buildings.
The winter season ended on Sunday and the resort is mostly deserted, but residents were shocked to see snow falling and hear rumblings in the sky earlier – especially after the sunbathing weather of the last few days. Following speculation the snow had caused avalanches, or that the pisteurs were blasting, it became clear a stranger phenomenon was at work after lights started flickering and TVs cut out.
Resident Alan Bell said on Facebook: “Definitely thunder snow, think my building just got hit, TV died, and everything went fuzzy out the window!”
Sarah Askew replied: “Judging by the fact that the electric has just flicked on and off I reckon it’s thunder and lightening while it’s dumping. Is that possible?”
It certainly is possible and could be due to clouds moving over warmer air above Tignes lakes, which have heated up in the summery weather over the past weeks. It’s basically a thunderstorm except that snow falls instead of rain.
According to BBC weather presenter John Hammond, it occurs when the atmosphere is unstable and the layer of air closest to the ground is cold enough to create snow, but still warmer than the air above it. As the warm air rises, water droplets condense to form cumulonimbus clouds. Lightning occurs when these rub against each other, and thunder is the sound of the lightning.
So that’s the science bit. If your TV’s not working, the good news is there might soon be enough snow out there to dust of the skis!