A persistent blizzard blanketed large parts of Spain with an unusual amount of snow on Saturday, killing at least four people and leaving thousands trapped in cars or at train stations and airports that suspended all services.

The national weather agency reported that as of 7 a.m., the snowfall in Madrid reached a level unseen in half a century.

The Interior Ministry said a 54-year-old man was also found dead in Madrid under a big pile of snow.

In Madrid, authorities activated a red alert for the first time since the system was adopted four decades ago and called in the military to rescue people from vehicles trapped on everything from small roads to the city's major thoroughfares.

As of Saturday evening, Spanish security services had rescued all the people who were trapped in vehicles — over 1,500, Interior Minister Fernando Grande-Marlaska said.

The storm is expected to be followed by a severe drop in temperatures in the coming days, the agency said.

Adolfo Suárez Madrid-Barajas International Airport, the main gateway in and out of Spain, will remain closed at least until Sunday, Ábalos said, after the blizzard bested machines and workers trying to keep the runways clear of snow.

The storm had caused serious disruptions or closed over 650 roads, according to Spain's transit authorities, which urged people to stay indoors and avoid all non-essential travel.