unmitigated disaster

Translations
полная катастрофа
The event was an unmitigated disaster due to the heavy rain.
Мероприятие было полной катастрофой из-за сильного дождя.
Definitions
An unmitigated disaster refers to a situation or event that is completely disastrous and without any reduction in severity or impact. It implies that the negative consequences are total and cannot be alleviated or lessened in any way.