A firefighter has died during a flood rescue in Austria and one person has drowned in Poland, as torrential rain caused by Storm Boris continues to wreak havoc across Central and Eastern Europe.

The Austrian province surrounding Vienna has been declared a disaster area, with its leaders speaking of "an unprecedented extreme situation".

In Romania, where four people were killed on Saturday, the prime minister says two others are missing, while several remain unaccounted for in the Czech Republic.

The floods caused by Storm Boris proved deadly in Romania on Saturday, where four people were killed during floods in the south-eastern region of Galati.

"We are again facing the effects of climate change, which are increasingly present on the European continent, with dramatic consequences," Romanian President Klaus Iohannis said on Saturday.

Extreme precipitation is becoming more likely in Europe, as across much of the world, due to climate change.

A warmer atmosphere can hold more moisture, which can lead to heavier rainfall.

Storm Boris has already brought extreme amounts of rain across central and eastern Europe, with more torrential downpours in the forecast through until at least the end of Monday.

Some of the highest rainfall totals so far have been in the Czech Republic. At Lysa Hora in the mountains in the west of the country, 288mm of rain has fallen since Thursday. This is around three months’ worth of rain in just three days.