The heaviest snowfall in decades blocked roads across Israel and the West Bank Saturday, while torrential rains flooded areas of the Gaza Strip.

The heavy snow, which stopped falling Saturday afternoon, prompted Israeli authorities to interrupt the Jewish sabbath to lay on relief trains.

Nationwide, some 30,000 households were without electricity, nearly 9,000 of them in Jerusalem, the Israel Electric Corp said.

Jerusalem city workers managed to clear most roads of drifting snow but appealed to residents to stay at home as fallen trees posed a persistent traffic hazard.

Few had ventured out, apart from observant Jews walking to synagogues.

The two main highways into the city, which climb to around 795 metres (2,600 feet) above sea level, remained closed in both directions for a third straight day.

Jerusalem-based meteorologist Boaz Nechemia told AFP that between 45 and 60 centimetres (18-24 inches) of snow had accumulated in the Holy City by Saturday.

"We haven't had such a snowfall in some 70 years," he said, noting that a metre of snow fell on Jerusalem in 1920.

With road travel almost impossible, authorities laid on free trains to Tel Aviv and Haifa on the coast, interrupting for the first time ever the shutdown of public transport on the Jewish day of prayer and rest, which runs from sundown on Friday to Saturday night.

The army said it was using armoured vehicles to distribute aid to areas cut off by the bad weather.

Schools in Jerusalem, Safed and other cities would not reopen Sunday, with the Jerusalem municipality explaining that it had to evaluate damages at educational institutions before the did.

Channel 2 television said an initial estimate put the damages at $85 million (62 million euros).

A police spokeswoman told AFP four people had died due to weather-related accidents since Thursday night.

Access to West Bank cities such as Ramallah remained blocked by heavy snowfall, an AFP correspondent said, with the only source of power in many cases being private generators.

Low ground on the coast was spared the snowfall, but torrential rains left areas of the Gaza Strip submerged.

Gaza was "a disaster area with water as far as the eye can see," the UN Relief and Works Agency for Palestine Refugees said.

The territory's Hamas rulers said 5,500 people had been rescued and sheltered after their homes were flooded on Saturday.

Gaza health services said a person died from asphyxiation trying to heat his home, and hundreds suffered weather-related injuries.

In some places, security forces and rescue workers were evacuating residents using small boats.

Hamas' press office also claimed that dozens of homes had been flooded in a village near Deir al-Balah in southern Gaza after "Israel opened the dams near the border on the east of the Strip at Wadi al-Salqa."

As a result of the flooding, 200 people were evacuated, the office added.

Gaza's Coastal Municipalities Water Authority said there are more than 15 areas that are heavily flooded.

A government estimate put initial damages at $64 million.

On Friday, Israel opened the Kerem Shalom crossing into Gaza to deliver gas for domestic use and to fuel pumps to drain the floodwater.

An official of the Hamas government said Israel would open the crossing again on Sunday to deliver fuel to the Palestinian territory's sole power plant, which is currently not operational.