More than 5,000 people in Gaza have been evacuated from their homes because of severe floods caused by torrential rain, Palestinian officials say.
Rescuers have had to use rowing boats to reach residents trapped by rising floodwaters.
United Nations officials have described parts of the northern Gaza Strip as a disaster area.
The winter storm, called Alexa, has covered parts of the West Bank and Israel with heavy snow.
Unusually harsh winter weather is causing disruption across the region.
A spokesman for the UN Relief and Works Agency (UNWRA) for Palestine Refugees said that large swathes of Gaza had "water as far as the eye can see".
"Areas around Jabaliya have become a massive lake with 2m-high waters engulfing homes and stranding thousands," the spokesman added.
Gaza's Hamas government says thousands of people have been moved to schools and other temporary shelters after the heavy rain over the past four days.
The BBC's Middle East correspondent, Yolande Knell, says many homes in Gaza are poorly built and the territory lacks basic infrastructure.
It is suffering fuel shortages which are causing power cuts.
Areas in the West Bank and Israel have seen the heaviest snow for decades.
Roads into Jerusalem are closed to private cars.
Officials say around 30,000 homes are without electricity in Israel.