By Lizbeth Diaz and Anahi Rama
MEXICO CITY, Sept 19 (Reuters) - Tropical Storm Manuel lashed Mexico's northwest coast with heavy rains on Thursday, prompting evacuations and adding to flash floods that have unleashed chaos across Mexico and killed at least 97 people.
Storms have inundated vast areas of Mexico since late last week, wrecking roads, destroying bridges and triggering landslides that buried homes and their occupants. Roads became raging rapids in the Pacific resort of Acapulco, stranding some 40,000 tourists.
Emergency services said heavy rains were beating down on the northwestern state of Sinaloa and that hundreds of people had been evacuated from coastal communities.
The U.S. National Hurricane Center said an area of low pressure over the oil-producing southern Gulf of Mexico had a 60 percent chance of becoming a tropical cyclone over the next 48 hours and could dump heavy rains on already flooded areas in southern and eastern Mexico.
The fresh misery comes after tropical storms Ingrid and Manuel converged on Mexico from the Gulf and the Pacific over the weekend, triggering the flash floods.
Ingrid dissipated, but Manuel then strengthened and gained hurricane strength before it was downgraded again to a tropical storm. Manuel was expected to weaken further to a tropical depression later on Thursday.
More than a million people have been affected across the country, and 50,000 have been evacuated from their homes.
"It's raining really heavily. I saw lots of fallen trees on my way to work," said Cristian Nunez, 26, a hotel receptionist in Culiacan, the capital of Sinaloa state. "Many employees didn't make it in ... we're basically alone."
Winds blew off the roofs of houses and 11 rivers in the state broke their banks. Residents waded through muddy, chest-high waters in some areas.
The flooded tourist resort of Acapulco further south, which was hit by looting, was still reeling on Thursday. Tens of thousands of people remained trapped in the city, awaiting evacuation as airlines and the armed forces worked to get them home.
MUD BURIES HOUSES
Some 58 people were still missing after a mudslide in Atoyac de Alvarez, a municipality near Acapulco in Guerrero state, President Enrique Pena Nieto said on Wednesday night. Pena Nieto said 288 people had already been rescued from the site.
Hotels in the state of Baja California Sur, home to the popular beach resorts of Los Cabos, which are popular with U.S. tourists, reported rain and wind on Wednesday, but nothing like the conditions seen in Acapulco.
As the cost of the flooding continued to mount, the finance ministry said it had around 12 billion pesos ($925.60 million) available in emergency funding.
The storm damage comes after the government had already slashed its growth forecast for the Mexican economy this year to 1.8 percent, and piles new pressure on government finances at a time when it had already proposed running a budget deficit to boost infrastructure spending.
Gabriel Casillas, head of economic analysis at Banorte, said the storms could shave between 0.1 and 0.3 percentage points off gross domestic product in the third quarter if economic activity is interrupted for 10 days in 16 badly-affected states.
"We haven't seen two such aggressive weather phenomena hitting at the same time in recent years," Casillas said. "We just don't yet know how long economic activity will be knocked out."
He said he expected the additional impact to an already weak economy, coming on top of concerns about the health of the U.S. economy voiced by the Federal Reserve this week, would push the central bank to cut its benchmark rate again in October.
While all but two of Mexico's ports remained open to large ships, including its three main oil export hubs along the Gulf, nearly 40 ports along both the Gulf and Pacific coasts were closed on Thursday morning to smaller boats, the transport ministry said.
State oil monopoly Pemex said it had dispatched technicians to fix a ruptured 12-inch (30 cm) oil pipeline from the Gulf port of Madero inland to Cadereyta, which connects two refineries.
The pipeline was damaged when the Pablillo River burst its banks due to heavy rains.