Some 2,000 people were trapped in their vehicles overnight as heavy snowfall cut off several roads in eastern Spain, authorities said.
The army's emergency unit said that it was distributing blankets and hot drinks to hundreds of people stranded on the A3 highway linking the capital, Madrid, to the coastal city of Valencia and on other roads in the region.
Soldiers and firefighters used snowploughs to try to clear the snow, managing to open A3 traffic towards Valencia, although it remained blocked towards Madrid.
Some train services in the region were also disrupted.
Heavy snow and rainstorms have hit many parts of Spain this week, with some eastern coastal tourist towns reporting their first snow in decades.
The Aemet weather agency said more snow and freezing temperatures were expected on Friday.