(CNN) — Hurricane Hanna weakened to a tropical depression after making landfall as a hurricane along the Gulf Coast of southern Texas on Saturday evening, bringing heavy rains and threats of flooding to parts of the state already reeling from the coronavirus pandemic.

“Any hurricane is an enormous challenge,” Gov. Greg Abbott said in a news conference Saturday. “This challenge is complicated and made even more severe, seeing that it is sweeping through an area that is the most challenged area in the state for Covid-19.”

Hanna made landfall Saturday evening on Padre Island, south of Corpus Christi, according to the National Hurricane Center. It was the first hurricane of the season in the Atlantic and had sustained winds of 90 mph, making it a high-end Category 1 hurricane.

By Sunday evening it was downgraded to a tropical depression, with maximum sustained winds of 35 mph, and was slowly dying over the mountains of northern Mexico. However, it still posed a threat for rain in the drenched Rio Grande Valley, where more than a foot of rain has fallen.

A flash flood emergency remained in effect for Hidalgo County, Texas, as roads and highways are underwater, prompting water rescues.

Widespread rainfall totals are between 4-6 inches, but some places have seen a foot of rainfall. There is still the chance for 2-4 inches of rain in parts of southern Texas as well as the chance of isolated tornadoes through the rest of Sunday.

In Corpus Christi, part of a popular pier collapsed, CNN affiliate KRIS reported, and high waters encroached on the Art Museum of South Texas.

Abbott issued a disaster declaration for 32 counties in the state and has also issued a federal emergency disaster declaration request. Urging extreme caution, Abbott warned residents across the state not to forget about the virus because of the storm.

FEMA approved a Federal Emergency Declaration following the storm’s landfall, Gov. Abbott’s office said in a news release on Sunday.

Officials in Hidalgo County, where several of the affected cities are located, reported overwhelmed hospitals last week filled to capacity and a judge ordered residents to shelter at home following upticks in both coronavirus cases and hospitalizations.

“This is a time in response to a hurricane where sometimes people will come together, come together to shelter, come together just as close family come together, as friends come together to respond,” Abbott said. “That coming together will continue to provide the ability for Covid-19 to transmit from one person to another.”

‘Dramatic’ flooding, governor says

Some of the southernmost parts of Texas received more than a foot of rain as the center of the storm crossed over to northeastern Mexico, CNN meteorologist Derek Van Dam said.

This led to widespread flooding in the Rio Grande Valley town of Mission, where the National Weather Service declared a flash flood emergency. There were numerous reports of water rescues, mainly from cars stuck in rising flood waters. Parts of US Highway 83 were impassable.

“We’ll continue to see dramatic waves of flooding including flash flooding that will come upon people suddenly. One moment they will be in an area … where it seems like there’s a little rain and then moments later, they could be washed in water up to their doors, if they’re in their cars, up to their knees, if they’re walking around,” the governor said Saturday.

Even as the storm weakens in the mountains of northern Mexico, additional rainfall is possible overnight. There is also a risk of isolated tornadoes. A confirmed EF0 tornado, with winds between 70-75 mph, struck the Brownsville airport early Sunday.

Meanwhile, another potential tropical system that could develop over the next five days was trekking behind Hanna across the Atlantic Ocean, Van Dam said.

Thousands without power

Tropical storm-force winds in parts of Texas could cause power outages and damage to buildings and trees, the weather service said. Along with the possibility of brief spin-up tornadoes, Van Dam said, and there will still be dangerous rip currents and localized beach flooding along the coast.

In Mission, officials said early Sunday morning emergency responders had already been dispatched to several homes for water rescues. A tornado warning was issued through early Sunday morning and officials reported thousands of residents were left without power, after heavy winds caused damage to power lines and traffic signals.

“Electricity crews must shelter in place due to wind speeds & the rain,” the City of Mission said on Twitter. “You’re asked to only report downed power lines or safety hazards. Crews will continue to respond to outages when it’s safe to do so.”

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