On 15 July, Switzerland's weather service warned that flooding in the country would worsen over the next few days, potentially equalling the levels of the 2005 "flood of the century" and that there was a particularly high risk of flooding on Lake Biel, Lake Thun and Lake Lucerne, as well as a risk of landslides.[1][16] That day, the water level in Lake Lucerne reached the highest warning level.[17]