Nearly three days after Hurricane Harvey made landfall in Texas, more statewide resources are being deployed to address rescue efforts in Southeast Texas. 

Gov. Greg Abbott announced Monday he has activated the entire Texas National Guard in response to Harvey, bringing the total number of deployed personnel for rescue efforts to 12,000. "It is imperative that we do everything possible to protect the lives and safety of people across the state of Texas as we continue to face the aftermath of this storm," the governor said in a released statement.  

Houston Mayor Sylvester Turner said Monday that first responders were focusing first on the elderly, disabled and those in life-threatening situations. 

"Our goal is to try to reach everyone today and get them out of stressful situations," Houston Mayor Sylvester Turner said Monday. 

Houston, the fourth largest city in the nation, was one of the many areas in Texas devastated over the weekend — and some parts of the state may receive more than 50 inches of rain in the coming days, which would break state records. 

For a glimpse into the scope of Harvey's impact in Texas, the 54 counties included in Abbott's Texas disaster declaration make up 41 percent of the state's 27.9 million population. On top of that, the Insurance Council of Texas has estimated Harvey-related damages will top Hurricane Ike's $12 billion clean up in 2008. 

Relief efforts are continuing around the state, too. Volunteer firefighters in smaller Texas towns are rescuing people trapped by the floods, and shelters in San Antonio and Austin are filling up. In Dallas, Mayor Mike Rawlings announced Monday that the city — home to more than 1.3 million people — would begin receiving evacuees affected by the storm that afternoon. 

At the federal level, Federal Emergency Management Agency Director Brock Long said at a news conference Monday that recovery efforts in Texas would require "a whole community effort from all levels of government, and it's going to require all citizens to get involved." 

On Tuesday, President Donald Trump is headed to Texas, where he'll arrive at Corpus Christi International Airport at 11 a.m., per a White House pool report.