More than 1,000 soldiers and firefighters are still working to control the flames of a forest fire the killed at least 62 people in Portugal this weekend. Cooler overnight temperatures have helped to contain some of the blazes. Inaccessible hill ranges 90 miles northeast of Lisbon are still experiencing fires.

Weather in your inbox

Forecast Location

Sign Up

By signing up you agree to the Terms & Privacy Policy. Unsubscribe at any time.

Many of the deaths occurred as the fire crossed a highway, trapping motorists in their cars between Figueiró dos Vinhos and Castanheira de Pêra, the New York Times reported.

(MORE: Latest News from the Portugal Fires)

Portugal is observing three days of national mourning after Saturday's deaths. Prime Minister Antonio Costa described the event as "the biggest tragedy of human life we have known in years." 

Portuguese forestry guards and investigators determined that a tree struck by lightning during a dry thunderstorm in the Pedrogao Grande area caused the fires. Compounded with temperatures of 104 degrees and strong winds, the fire burned quickly out of control. 

The Portuguese government announced new measures to combat wildfires this March, including restrictions on eucalyptus plantations, but not all reforms have been legally enforced yet. 

MORE FROM WEATHER.COM: Bangladesh Landslides Claim More Than 140 Lives