An ongoing heat wave is fueling wildfires, causing heat-related deaths and breaking records in Western Europe.

British authorities are issuing dire warnings, as temperatures may reach 104 degrees Fahrenheit in southern Britain, a region usually known for moderate summer heat, with July highs in the 70s. It's the first time such a forecast has been made in the area.

The heat poses a serious health risk, as people will need to take precautions to avoid heat-related illness. In Britain, few homes, apartments, schools or small businesses have air conditioning, making residents particularly vulnerable.

Extreme heat is also endangering the environment and homes, with wildfires raging in Portugal, Spain and France.

British authorities have described it as a "national emergency" and southern Britain is under an “extreme” heat warning for the first time on record.

London Underground subway passengers are being advised not to travel on Monday and Tuesday, because the heat is expected to affect rails and might cause delays, authorities said.