This event is unprecedented & all impacts are unknown & beyond anything experienced. Follow orders from officials to ensure safety. #Harvey pic.twitter.com/IjpWLey1h8

— National Weather Service (@NWS) August 27, 2017

WATCH: U.S. Coast Guard footage from Texas shows the scale of flooding caused by Harvey pic.twitter.com/KBjOx1rAly

— NBC News (@NBCNews) August 27, 2017

Estimated 1,500 – 2,000 water rescues have taken place due to #Harvey, as workers continue to locate survivors. https://t.co/Vn8ljuD8yL pic.twitter.com/4OK6OKYh8G

— ABC News (@ABC) August 28, 2017

A powerful moment—CNN's @edlavaCNN assists in a flood rescue outside of Houston.#Harvey #Houston #HurricaneHarvey https://t.co/2hRnvbMfLL

— Scott Dworkin (@funder) August 28, 2017

Houston police puts out call to "anyone with a boat who can volunteer to help" in Harvey response pic.twitter.com/j0NZAoAAEm

— NBC News (@NBCNews) August 28, 2017

These videos illustrate how Harvey’s floodwaters are devastating Houston. https://t.co/OQvqoV8czx pic.twitter.com/d0gEZp5mtk

— Slate (@Slate) August 27, 2017

Tropical Storm Harvey in photographs https://t.co/oVhqhRHMH7 pic.twitter.com/41hvJngrJ9

— The New York Times (@nytimes) August 27, 2017

All of the @washingtonpost online is free to read right now: ‘Catastrophic’ Harvey causes deadly floods in Texas https://t.co/c159GjjQRn pic.twitter.com/czFJ6lexeI

— Anna Fifield (@annafifield) August 27, 2017

All readers have open access to Tropical Storm Harvey coverage. NYT lifted the paywall on articles about the storm. https://t.co/8mti27dSwp

— The New York Times (@nytimes) August 27, 2017

Never thought I'd do an interview like this standing on Interstate 45 south of Houston. https://t.co/t7C0lVAMep

— Ed Lavandera (@edlavaCNN) August 27, 2017

#Harvey pushes U.S. gasoline prices up more than 6 percent to the highest level in more than two years https://t.co/YWsNP9FFVI pic.twitter.com/cWOTMjIXl7

— Reuters (@Reuters) August 27, 2017

In statement, Mexican Foreign Ministry says it has offered help in Harvey response "as good neighbors should always do in trying times." pic.twitter.com/Cfu8znIne4

— NBC News (@NBCNews) August 27, 2017

Trump attacks Mexico, NAFTA, Dem senator in morning tweets as Harvey batters Texas https://t.co/v4sOCR6tUd pic.twitter.com/9XsKcYzdge

— The Hill (@thehill) August 28, 2017

Trump aide on Arpaio pardon: "Not too many people care" because of Hurricane Harvey https://t.co/XwycpjUJkj pic.twitter.com/VMq7VMaNgS

— The Hill (@thehill) August 27, 2017

Trump boasts of 2016 election victory after tweeting about Hurricane Harvey https://t.co/ZLxvuMOJNA pic.twitter.com/dz9arSCZnl

— The Hill (@thehill) August 27, 2017

Pres. Trump will travel to Texas on Tuesday in the wake of Hurricane #Harvey causing destruction and record flooding https://t.co/v2W10G8uDT pic.twitter.com/mHxlSsvFkJ

— ABC News (@ABC) August 27, 2017

Thank you to all the first responders and people helping each other out. That's what we do as Americans. Here's one way you can help now. https://t.co/iGfE8rAoAu

— Barack Obama (@BarackObama) August 27, 2017