Forest fires are cutting a swathe across North America and western Europe, destroying tens of thousands of hectares and leading to mass evacuations.

The premier of British Columbia has declared a state of emergency in southern Alberta, where firecrews are trying to contain a large blaze which has so far destroyed 60 homes and a sawmill and led to the evacuation of about 7,500 people. Aircraft are dropping water onto the flames, while firefighters struggle to create fire-breaks.

  Meanwhile, across the border in Washington a 31,000ha blaze is raging in Farewell Creek.

About 100 elite firefighters have been dropped by helicopters to dig firelines in front of the blaze. Lower temperatures and rising humidity have helped crews build a containment line on the north-west section of the fire.

In Europe, forest fires in Portugal have claimed nine lives and destroyed thousands of hectares of forest. The country’s prime minister said the government would declare the fires a “public calamity”, which could lead to compensation for those affected.

Firefighting planes from Italy and Morocco are helping fight the flames, which are burning in 15 of the country’s 18 districts.

Forest fires in the Var region of the French Riviera have claimed the lives of at least four people and forced the evacuation of thousands of others. The fires, which may have been caused by arson, have so far burned 19,770 acres, while an earlier blaze in the Massif des Maures affected 24,710 acres.