Flooding killed three people in Dhamar, 70 kilometers south of the capital Sanaa. Three others, including two young girls, died in the province of Hodeida, about 270 kilometers west of the capital.
Another six people were struck dead by lightning in Manakhah, which lies midway between Hodeida and Sanaa, and in the southwest of the country.
At least five people were killed by floods that swept through Dhamar at the start of Yemen's rainy season in February. Ten people were killed in similar flooding in April last year.
Californians evacuated
And in the United States, hundreds of people have been evacuated from their homes as relentless storms pounded northern California, breaking levees, causing mudslides, and undermining coastal roads.
Several hundred people, most of them senior citizens, were evacuated from houses and mobile home parks near the state capital of Sacramento after a levee breach in the county of Merced.
Displaced residents took refuge in a local high school gymnasium and with relatives as the levee was repaired and flood water rerouted.
An estimated 50 houses were threatened by the flood.
A different levee break in Sacramento County flooded farm land but didn't endanger any homes. Northern California has recorded one of the wettest spring seasons on record, drenching the region and darkening the spirits of residents accustomed to an abundance of sunshine.
Soggy soil has slid on hillsides in residential communties in the San Francisco area, closing roads and jeopardizing some homes. No casualties or injuries were reported.
Floods in Europe
Parts of Europe have also been deluged by floodwaters.
Hungary drafted in thousands of troops to bolster the country's flood defences as the death toll from raging rivers and floodwaters mounted in Central Europe.
Austria announced its first victim, an 18-month old boy who died after he fell into the swollen Duerre Ager river while playing in front of his parents' house near Salzburg, in the west of the country.
At least a dozen people have already lost their lives in floods that have hit Austria, the Czech Republic, Germany and Slovakia over the last week. A handful of people are still missing.
Six thousand Hungarian soldiers, 5,000 police, 1,000 firemen and 815 border guards have been dispatched to some of the worst-hit areas in the country today as the Danube climbed to record levels in Budapest.
In the Hungarian capital, where a state of emergency has been declared, the Danube reached a record 8.48 metres and was expected to peak at 8.60 metres.
In Lower Austria a second flood protection barrier broke and troops and firemen were sent to close the 60 metre breach in the defence against the raging March river.
More people were evacuated overnight, after part of the flood defences in nearby Duernkrut gave way. Fire departments from up to 100 kilometres away were mobilised to help.
The Czech Republic's swollen River Elbe - running at more than four times its normal level - started to fall for the first time in a week, giving hope to thousands of people threatened by flooding and thousands already forced to flee their homes.
In eastern Germany, the Elbe also appeared to have stopped rising but the weather forecast for Central Europe is mixed.
Czech weather forecasters warned that the next day would be crucial, with three centimetres of rain expected in the east and hotter weather which could thaw remaining snow.