Ticino's Onsernone Valley records the highest amounts of precipitation

The "event" is not over yet, explained Marco Gaia, Head of Forecasting and Consulting at the Federal Office of Meteorology and Climatology (MeteoSwiss) in Locarno-Monti, at the request of the Keystone-SDA news agency.

MeteoSwiss has therefore extended the level 4 (out of 5) rain warning for southern Switzerland until 6 a.m. on Friday morning. Originally, the warning had been issued for Thursday until midnight.

Between midday on Wednesday and early Thursday afternoon, 205 millimetres of rain fell in Mosogno in the Onsernone Valley in Ticino. This makes the municipality the leader, as Gaia noted.

The spread of precipitation over the main Alpine ridge to the north has so far been somewhat weaker than expected, according to a MeteoSwiss blog entry. From the Urseren Valley via the Tavetsch and the valleys south of the Surselva to the Avers, "only" 30 to 50 millimetres of precipitation have been measured so far.

In the Jura, north-western Switzerland, the western foothills of the Alps and locally in Appenzell, 30 to 50 millimetres have fallen. The reason for the rainfall is the extensive low pressure system Erin, centered north of Ireland. Erin is a former hurricane that has turned into an extratropical depression.

Precautionary evacuations in the Misox

On Wednesday evening, the access roads to the Pontirone, Malvaglia and Bavona valleys in Ticino were closed due to the forecast heavy rainfall.

In Lostallo in Misox GR, eleven people were also evacuated on Wednesday evening as a precaution. Seven others had temporarily left their homes voluntarily, the municipality of Lostallo stated at the request of Keystone-SDA.

According to Marco Gaia, the rainfall is likely to be weaker overall than during the two severe storms in June last year. Back then, a total of nine people lost their lives in Misox and the Maggia and Bavona valleys. Two people are still missing.