Spain’s government has called on citizens to stay at home in the wake of a record-breaking winter storm that has produced Madrid’s biggest snowfall for at least 50 years and that threatens to bring about the coldest temperatures since the second world war.

The impact of the storm — dubbed Filomena — is all the greater as the national government and the Madrid region have both resisted imposing a second coronavirus lockdown despite rising infection rates in recent weeks.

“This is not over,” Fernando Grande-Marlaska, interior minister, said at a press conference on Monday. “It is necessary to avoid any travel that is not necessary . . . We are going through the most adverse meteorological conditions in recent history.”

Madrid, the centre of Spain’s transport infrastructure, is relatively unused to snow.

Two days after parts of the city were coated with 50-60cm of snow — the heaviest fall since at least 1971 — roads in much of the capital remain impassable except by foot. One of the city’s jails has been left without water or heating, a medical workers union has complained that some of its members have been stranded at primary care clinics since Friday and personnel at Madrid hospitals have worked shifts of up to 48 hours. Salvador Illa, health minister, hailed a young doctor who walked 17km through the snow for his shift at Madrid’s Puerta de Hierro hospital.

The Madrid region has decided to keep schools closed until next Monday because of the effects of Filomena.

Local and national officials fear that some of the biggest tests could be yet to come, with the coldest temperatures since 1945 set to turn the snow into ice.

Temperatures as low as minus 10 degrees centigrade were expected to hit part of the greater Madrid region on Tuesday morning, while the state meteorological agency predicted that other parts of the country, such as Soria and Cuenca, would experience drops to minus 14 degrees or lower.

The authorities say they have cleared many of Spain’s principal highways. But, as of Monday evening, the transport ministry said, about 600 highways across the country — from Galicia in the north and Catalonia in the east to Andalucía in the south — remained affected.

Officials in the Madrid region warn that residential streets may not be unblocked until the weekend or even later.

But Mr Grande-Marlaska added that the distribution of the BioNTech/Pfizer coronavirus vaccine was taking place “with total normality” — although a supply flight to Madrid was diverted to the Basque city of Vitoria — and that only about 10 “urban zones” were suffering from power cuts.

Trucks that had been stranded on the highway since Friday have now been able to deliver supplies to Madrid’s main food market, but a number of neighbourhood supermarkets have already run out of much of their fresh produce.

The storm has also taken a heavy toll on the capital’s trees: Madrid town hall officials estimate that 150,000 of the 800,000 trees in the city’s parks and streets have been damaged by heavy burdens of snow and ice.