Officials say Texas City hasn't seen this much rainfall in more than two decades, adding that all pump stations are fully operable. Some first responders are using dump tracks to navigate flooded roadways.
For residents displaced by high water, the Red Cross has opened a shelter at Bay Harbour United Methodist Church on 3459 Deke Slayton Highway in League City.
PHOTOS: Flooding in Galveston County
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No water rescues have been reported, but city officials say they are concerned by the number of stalled vehicles abandoned on flooded roadways.
Palmer Highway was especially hard-hit, with many motorists forced to ditch their vehicles in high water. All along the roadway, which remained submerged at nightfall, motorists had attempted to protect their cars by parking them on the median.
In Galveston, record amounts of rainfall had fallen by mid-morning. The city recorded more than 6 inches by Saturday evening, nearly tripling the previous record.
The National Weather Service in Houston/Galveston has issued a Flash Flood Watch for portions of southeast Texas through Sunday evening. A Flash Flood Warning has also been issued for Galveston and Brazoria counties until 8pm.
Throughout much of southeastern Texas, a Flash Flood Watch has been extended through Sunday evening.
For the rest of the weekend, pockets of moderate to heavy rainfall are likely for some areas around Houston. Through Monday, the City of Houston could see up to 6 inches of rain.
According to meteorologist David Tillman, areas within the city that see more than six inches could 'easily' see street flooding.
Some areas closer to the coast could see as much as 15 inches rain before it ends Monday afternoon.
As always, don't drive into areas that are flooded and never drive onto a flooded road.