TUXPAN, Mexico (CNN) -- Once a monster Category 5 hurricane, Dean was downgraded to a tropical depression Wednesday evening as it rapidly lost strength after battering Mexico's eastern coast.
A boy sits Wednesday amid the ruins of a house destroyed by Hurricane Dean in southeastern Mexico.
But the storm continued to be dangerous as it diminished. Heavy rain could cause life-threatening flash floods and mudslides in parts of southern and central Mexico, according to the National Hurricane Center in Miami, Florida. Up to 20 inches of rain could fall in some areas, it said.
That possibility was a big concern in Tuxpan -- about 45 miles north of where Dean made landfall -- where officials said that the Tuxpan River was flowing backward -- inland, rather than toward the ocean.
Authorities worried the influx of water, possibly coupled with rains over the mountains to the west, could lead to flooding.
Dean hit the Mexican shore for the second time near the key port city of Veracruz Wednesday, with top sustained winds of 100 mph (160 kph) -- making it a Category 2 storm at the time of landfall, according to the hurricane center.
It has been steadily weakening since. At 11 p.m. ET, Dean's winds had dropped to 35 mph, the center said in its last public advisory on the system. The storm was moving west at near 21 mph.
All tropical storm and hurricane warnings have been canceled.
As Dean approached the coast, its winds bent the tall palm trees in Nautla -- a town of about 3,000 people some 20 miles (32 kilometers) south of where the storm made landfall.
Dean has fluctuated in strength since slamming into Mexico's Yucatan Peninsula on Tuesday as a Category 5 storm -- the most extreme level on the Saffir-Simpson scale of hurricane intensity.
After losing some intensity crossing the peninsula, Dean regained some strength Wednesday over the warm waters of the Gulf of Mexico.
In preparation, Mexican government officials on Tuesday traveled from beach to beach warning people to prepare for the weakened hurricane.
Authorities set up temporary shelters around Tuxpan with the capacity to hold thousands, according to Ramon Rodriguez, municipal president of the city.
About 5,000 people were evacuated in the urban areas and 4,500 people fled the rural areas, he said. Watch how Tuxpan remains in danger, even after Dean's landfall »
On the Yucatan, tourist areas -- including Cozumel and Cancun -- dodged a bullet, but President Felipe Calderon expressed concern for some of the peninsula's poor Mayan communities.
"We still have to know what happened in the more isolated communities," Calderon said before leaving a summit in Canada with President Bush and Canadian Prime Minister Stephen Harper.
Ancient Mayan ruins in the town of Tulum, south of Cancun, held up well, resident Enrique Perez said. But the town was battered. Local officials said about a third of the hotels and beach cabins in Tulum were damaged, Reuters reported.
The Mexican president headed to the Yucatan, where he toured hurricane-hit areas in the state of Quintana Roo.
"Fortunately, based on initial information, the damage is not as bad as we had expected it would be, thank God," Calderon said. He credited preventive measures taken by federal and state workers.
Calderon said the government suspended oil production near Campeche, Mexico's main oil production center, as Dean passed -- cutting off about 2.5 million barrels of oil per day -- and evacuated nearly 20,000 workers from oil platforms in the area.
Downed power lines and damaged buildings were reported in Mexico and northern Belize. But even in the hardest-hit area, Red Cross officials said, no deaths were reported and only one injury, which was minor. See CNN correspondents track Dean through Mexico »
Streets were flooded in Chetumal, just south of where Dean's center made its initial landfall around 4:30 a.m. Tuesday (5:30 a.m. ET) with maximum sustained winds of 165 mph (266 kph), according to the hurricane center.
Power was knocked out, but most of the city's 130,000 residents appeared to have heeded government warnings to seek shelter or evacuate.
Dean is being blamed for at least nine deaths in its march across the Caribbean, including two in Jamaica, two in Haiti, two in Martinique, two in Dominica and one in St. Lucia. See Dean's impact on the Yucatan Peninsula »
Mexico's Yucatan resort region was devastated in 2005 by Wilma, a Category 3 hurricane, but residents learned a lesson from the fierce storm.
"This was a piece of cake compared to Wilma," Tourism Secretary Gabriella Rodriguez said.
Ahead of the storm, the Mexican government deployed 4,000 troops to the area, and a state of emergency was declared in the state of Campeche. E-mail to a friend
CNN's Rob Marciano, Suzanne Malveaux and Monica Trevino contributed to this report.
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