Hillsides collapse and rivers overflow after freak winter weather that affects more than half the country. Rains are severe in the mountains that are home to Monarch butterflies.

Mexico City - Freak winter rains across Mexico collapsed hillsides, sent rivers over their banks and left at least 15 people dead, officials said Friday.

The rain, which began early in the week and peaked Thursday, had relented by Friday morning, providing officials with their first good look at the damage.

More than half of the country was affected. Hardest hit was the western state of Michoacan, where at least 13 people were killed by landslides and flooding. An unknown number of people were missing Friday.

Rains were severe in the mountainous zone that is famous as a reserve for Monarch butterflies. At least 15,000 residents and 2,000 homes in Michoacan were affected, officials said.

Three children died when their home in Angangueo was overwhelmed by a flooded river, and two other people died under a landslide in Zitacuaro. A sixth victim was crushed beneath a collapsed wall of a home in Ocampo.

Two children drowned trying to cross the swollen Chapulin River in the central state of Guanajuato.

In metropolitan Mexico City, where flooding is an annual hassle during seasonal rains that begin in spring, several hundred families in the working-class Valle del Chalco community were evacuated early Friday after a sewage canal overflowed on the city's edge, spilling a river of waste.

In the capital's impoverished Iztapalapa district, 650 families were forced to flee their homes.

Rainfall of nearly an inch an hour caused widespread power outages and swamped traffic in water that reached bus windows.

The Mexican military was summoned to build sandbags dikes.

"We are experiencing one of the most difficult emergencies we have had in the city," said Mayor Marcelo Ebrard.

There was a silver lining: Officials said the copious rain had filled reservoirs outside Mexico City that are a key source of water for the metropolis. Water shortages had forced on-and-off rationing since last summer.