By Monday night, the rain showed no signs of letting up.

At least 13 people were reported killed in Ciudad Acuña, a Mexican border town west of San Antonio, after a tornado struck.

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Some parts of Austin are completely flooded with water after days of heavy rain.

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Police stretch tape across a flooded Sixth Street in the city on Monday after days of heavy rain.

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Austinite Lucas Rivas looks into the flooded Whole Earth Provisions Company on Lamar Street.

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Local river Shoal Creek is threatening to overflow.

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By Monday night, the rain showed no signs of letting up.

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In nearby Houston, fans who had just watched the Houston Rockets play the Golden State Warriors were forced to stay in the Toyota Center arena because of emergency flash flooding, while the video board provided news.

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Twitter user Jeff Syptak shared this photo of Interstate 45 in Houston on Monday night.

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The iconic picture of I-45 at N. main. Just crazy. Need to address this area's recent traffic backup. #Houstonflood pic.twitter.com/S2Gl76QasM
— Jeff Syptak (@JeffSyptak) May 26, 2015

Instagram user Maherfilms posted this picture of Trinity River near Dallas overflowing with water on Tuesday.

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We took our Inspire 1 out above the flooded Trinity River. Head over to maherfilms.com to see a once in a lifetime look at Downtown Dallas. #dji #inspire #drone #dallas #trinityriver #texasflood #downtowndallas #aerialvideography

A photo posted by Michael Maher (@maherfilms) on May 26, 2015 at 9:07am PDT

Twitter user @astrosguy tweeted out this image of flood water around Reliant Stadium in downtown Houston where the Texans play.

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Areas around Reliant Stadium completely under water. #houstonflood pic.twitter.com/UP8eoAJ8go
— Beer and Bae sball (@astrosguy) May 26, 2015

Another Houston Twitter user, Steve Helm tweeted this image showing the extent of the flood damage.

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Prayers for all affected by the #HoustonFlood- esp for the #poor who already struggle in "good weather." 3rd/5th Ward pic.twitter.com/Dt8cgRF73x
— Steve Helm (@javapastor) May 26, 2015

Houston Meterologist with AccuWeather, Becky Elliot tweeted out this image showing parts of Houston inundated with water.

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Blue=flood. People should not try to go anywhere in #Houstonflood this am. Good site for info. http://t.co/oIz8FkLcFU pic.twitter.com/ypjGxOVNH9
— Becky Elliott (@AccuWxBeck) May 26, 2015

And Twitter user Erin Ruberry posted this photo on Tuesday of the Houston Galleria Mall parking garage submerged underwater.

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Wow: The lower parking garage at Houston's Galleria mall is underwater (via @KHOULily) #houstonflood pic.twitter.com/TnRiSoB6EF
— Erin Ruberry (@erinruberry) May 26, 2015

Twitter user @PHILOCALYLOUIS shared these photos of the highway outside Houston.

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when you think its a river but it's actually a highway #houstonflood pic.twitter.com/idAROXGPXy
— stephanie (@PHILOCALYLOUIS) May 26, 2015

Wimberly, Texas was hit pretty hard by the storm, too, as shown by this image taken on Tuesday.

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Texas Gov. Greg Abbott spoke at a news conference at the Wimberley Community Center on Monday, detailing recovery efforts in the area.

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This cabin on the banks of the Blanco River was all but destroyed after flooding in Wimberley on Sunday.

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Department of Public Safety Trooper Marcus Gonzales walked on the Highway 12 bridge over the Blanco River which was blocked by large trees.

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Here is what it looked like under the bridge.

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This lucky family was rescued by firefighters after clinging to a tree near their home in Kyle, Texas during flooding on Sunday.

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Similarly, San Marcos Firefighter Jay Horton is seen here rescuing a woman from flood waters in San Marcos, Texas on Sunday.

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Flood waters covered the roads, businesses, and houses in San Marcos.

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The devastation in San Marcos was everywhere, as is evident by this mass of damaged cars and debris piled up against a line of trees.

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The New York Times posted this drone video showing the flood aftermath throughout Texas.

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Tons of water there, not enough water here...

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24 scary photos of the devastation caused by massive floods in Texas, Oklahoma, and Mexico

At least 13 people were reported killed in Ciudad Acuña, a Mexican border town west of San Antonio, after a tornado struck.

Some parts of Austin are completely flooded with water after days of heavy rain.

Police stretch tape across a flooded Sixth Street in the city on Monday after days of heavy rain.

Austinite Lucas Rivas looks into the flooded Whole Earth Provisions Company on Lamar Street.

Local river Shoal Creek is threatening to overflow.

By Monday night, the rain showed no signs of letting up.

In nearby Houston, fans who had just watched the Houston Rockets play the Golden State Warriors were forced to stay in the Toyota Center arena because of emergency flash flooding, while the video board provided news.

Twitter user Jeff Syptak shared this photo of Interstate 45 in Houston on Monday night.

Instagram user Maherfilms posted this picture of Trinity River near Dallas overflowing with water on Tuesday.

Twitter user @astrosguy tweeted out this image of flood water around Reliant Stadium in downtown Houston where the Texans play.

Another Houston Twitter user, Steve Helm tweeted this image showing the extent of the flood damage.

Houston Meterologist with AccuWeather, Becky Elliot tweeted out this image showing parts of Houston inundated with water.

And Twitter user Erin Ruberry posted this photo on Tuesday of the Houston Galleria Mall parking garage submerged underwater.

Twitter user @PHILOCALYLOUIS shared these photos of the highway outside Houston.

Wimberly, Texas was hit pretty hard by the storm, too, as shown by this image taken on Tuesday.

Texas Gov. Greg Abbott spoke at a news conference at the Wimberley Community Center on Monday, detailing recovery efforts in the area.

This cabin on the banks of the Blanco River was all but destroyed after flooding in Wimberley on Sunday.

Department of Public Safety Trooper Marcus Gonzales walked on the Highway 12 bridge over the Blanco River which was blocked by large trees.

Here is what it looked like under the bridge.

This lucky family was rescued by firefighters after clinging to a tree near their home in Kyle, Texas during flooding on Sunday.

Similarly, San Marcos Firefighter Jay Horton is seen here rescuing a woman from flood waters in San Marcos, Texas on Sunday.

Flood waters covered the roads, businesses, and houses in San Marcos.

The devastation in San Marcos was everywhere, as is evident by this mass of damaged cars and debris piled up against a line of trees.

The New York Times posted this drone video showing the flood aftermath throughout Texas.

Tons of water there, not enough water here...

Just how bad the California drought really is