HOUSTON, Texas - Hundreds of rescues already have been made in Houston and many more were expected Sunday as rescuers battling severe weather and heavy downpours tried hard to reach those left stranded in Harvey's wake, one day after the once-fearsome hurricane spun deeper into the Texas coastline in a blow that killed at least two people and injured up to 14. 

Throughout the region between Corpus Christi and Houston -- where rescue efforts increased as water levels rose to dangerous levels -- many people feared that toll was only the beginning. 

Authorities did not know the full scope of damage because weather conditions prevented emergency crews from getting into the hardest-hit places. And they dreaded the destruction that was yet to come from a storm that could linger for days and unload more than 40 inches of rain on cities, including dangerously flood-prone Houston, the nation's fourth-largest. 

The storm made landfall late Friday night as a Category 4 storm, with sustained winds of 130 mph that whipped coastal communities throughout the night. Winds slowed throughout the day Saturday as Harvey lost strength, becoming a tropical storm by Saturday afternoon. 

The storm was the first Category 4 hurricane to hit the continental United States in over a decade, and the first to make landfall in Texas since 1961. Texas Attorney General Ken Paxton said Harvey is "probably the biggest storm in [Texas] history."

Follow along below for updates on the storm. All times are Eastern unless otherwise noted.

8:30 a.m.:

In Houston, authorities were pleading with people not to leave their homes as a flood emergency was declared. 

The National Weather Service Houston/Galveston said Emergency Management officials are requesting that people get on the roof of their home if the highest floor becomes dangerous.

The National Weather Service said catastrophic flooding in the Houston metropolitan area "is expected to worsen and could become historic in association with Harvey."

8:00 a.m.: "Catastrophic flooding"

Harvey continues to cause "catastrophic flooding in southeastern Texas," the National Hurricane Center says.

One person was killed in Aransas County when in a fire at home during the storm, county Judge C.H. "Burt" Mills Jr. said. A second person died in flooding in Harris County, where Houston is located.

About 300,000 customers were without power statewide. Gov. Greg Abbott said it would probably be several days before electricity is restored.

3:35 a.m.: Houston rainfall totals eclipse 500-year rain level mark

Harris County Sheriff Ed Gonzalez tweeted that the rainfall totals in three hours had eclipsed the 500-year rain level mark.

Harris County Flood Control District meteorologist Jeff Linder tweeted there have been calls of people climbing into their attics due to floodwaters. According to Linder, 13-14 inches of rain fell in three hours.

The National Weather Service said Houston is in a catastrophic, life-threatening flash flood emergency. The flash flood emergency will last until 7 a.m.

1:50 a.m.: Fatality is confirmed from flooding in Houston

A motorist died Saturday after being stranded in the floodwaters from Harvey, County Judge Ed Emmett told CBS affiliate KHOU.  

KHOU reports the woman tried to get out of her car but didn't make it. A neighbor found her body.

Several major Houston roadways are underwater.

Houston mayor Sylvester Turner said the streets are "treacherous." 

11:35 p.m.: Flash flood emergency declared in Houston's Harris County

A flash flood emergency is in effect for Harris County, meaning life-threatening flooding is possible, CBS affiliate KHOU reports.

"We're seeing just incredible rainfall rights right now in the heart of Houston," said Jeff Lindner with the Harris County Flood Control District. 

The Harris County Sheriff's office tweeted that a man had been rescued from his car in three feet of rushing water.

Most areas have seen more than 2 inches in the last hour, according to KHOU. 

They've had more than 4 inches in the last hour in the Meyerland area and there is a threat of water in homes there, Lindner said. 

The Houston Office of Emergency Management tweeted that the Red Cross shelter is closing due to high water. The METRO Houston has suspended all bus and rail service.

The Fort Bend County Sheriff's Office is also reporting tornado sightings in Stafford, Missouri City and near US 90 and the Texas Parkway. 

Tornados have already caused damage in Cypress, Sienna Plantation, Katy, Richmond and Atascocita. 

9:40 p.m.: Coast Guard launches helicopter rescue

The Coast Guard said Saturday that it was responding to a call of seven distressed people in Aransas Pass, Texas.

The Coast Guard said it received the call at about 7 p.m. central time of seven people, one of which is reportedly on oxygen and had run out, in need of assistance. 

The Coast Guard said its Air Station Corpus Christi aircrews rescued in total 20 people and a dog after they received reports from watchstanders at Coast Guard Sector Corpus Christi Saturday morning and afternoon.  

7:50 p.m.: "Biggest concern" is the 20-30 inches of rain, Texas Gov. says

More than a foot-and-a-half of rain fell in just 24 hours in Victoria, Texas -- and by the time the storm is over, the city could get in only days the amount of rain it sees in one year, CBS News' Manuel Bojorquez reports.

"Our biggest concern is the possibility of between 20 and 30 inches of rain in areas ranging from Corpus Christi over to Houston," said Texas Gov. Greg Abbott. "Because of the flooding, one of the top focal points that we are concerned about is ongoing rescue and recovery." 

Angela and Mario Manzano are checking on the home they recently purchased.

"It's devastating because like I said, we're barely purchasing the home, we're still paying it off, to lose it now, it's going to be hard," Angela said.

Their home is in a low-lying area prone to flooding.

"If it was just the two of us, it would be different, but having our kids, that why we took, we just took the most important things -- our important documents and pictures that can't be replaced and that stuff," Angela said. 

7:30 p.m.: Inside Rockport, the city in the eye of Harvey

Ferocious winds and floodwater have left this quaint city on the gulf a disaster zone, CBS News' David Begnaud reports. Parts of the high school were torn to shreds. Harvey showed no mercy on the local First Baptist church. Some homes have collapsed into the water. 

"We went upstairs and looked out the window and down the road here it was a sheer wall of water, like 100 mph it was crazy," said Tim Freiburger. His garage was lifted up and jammed against the side of the house. 

"It was insane all you could do was just feel stuff pounding the house," he said. 

Residents of this senior living complex were stranded when portions of its roof torn away and emergency workers were unable to respond at the height of the storm. 

Nearly every police car in town has been damaged, but still officers were out Saturday, banging on doors, making sure no one was trapped. 

When the hurricane made landfall here late Friday night, the city was under a mandatory evacuation. 

"I'll take a while to get it all straightened backup," said Randy Bonnett, who has been through Texas hurricanes before but he says he will not forget Harvey. 

"You got three hours of hell and then an hour lull and then three hours hell," Bonnett said. 

7:10 p.m.: Millions in danger of potentially catastrophic flooding

Harvey is still going and it's not going anywhere for awhile, CBS News' DeMarco Morgan reports. There are over 1,000 people assigned to search and rescue operations. Near Corpus Christi on Saturday, the Coast Guard rescued 17 people whose vessels were in distress. The governor of Texas has issued a disaster declaration for 50 counties. Saturday morning, Galveston got pounded.

With the storm stalling out, now millions are in danger of potentially catastrophic flooding. More than three feet of rain could fall in some places. 

"We are just getting into this so people need to understand that the longevity of this is gonna go thru the weekend and even into the early part of next week," said Jeff Linder with the Harris County Flood Control in Houston.

Nearly 300,000 power outages have been reported and Corpus Christi is under a boil water order. Incredibly, no fatalities have been reported yet. In Rockport, where the storm took a direct hit, ten people were injured when the roof of a senior housing complex collapsed, according to local media reports. Hundreds of people were evacuated from a hotel there last night.

5:34 p.m.: White House releases photos of President Trump on teleconference call earlier Saturday

The White House said President Trump was briefed on the response to Harvey at Camp David, where he's spending the weekend.

4:11 p.m.: Coast Guard rescues 17 people

The Coast Guard says it has rescued 15 people onboard vessels near Port Aransas, Texas. Two Coast Guard helicopters were dispatched to help the ships earlier Saturday after receiving distress calls. 

The Coast Guard said in a release that seven people were rescued from the tugboat Sabine; four people from the Signet Enterprise; and four from the vessel Sandy Point. 

A man and a woman were also rescued in Houston, along with their dog. 

3:47 p.m.: President Trump thanks volunteers

3:31 p.m.: Harvey shuts down one-fifth of U.S. oil production
About one-third of the America's refining capacity reside in low-lying areas on the coast from Corpus Christi, Texas, to Lake Charles, Louisiana, the Associated Press reports.

The Bureau of Safety and Environmental Enforcement said Friday that workers were evacuated from 86 of 737 manned oil production platforms where oil and gas are pumped from the Gulf of Mexico.

The agency estimated that approximately 21.55 percent of oil production had been shut down along with 23.24 percent of natural gas production.

The AP reports, citing FlightAware, that nearly 1,200 flights were cancelled on Friday and Saturday, and an additional 485 flights for Sunday were cancelled.

2:27 p.m. President Trump receives update from cabinet officials
President Trump and Vice President Mike Pence met with cabinet members and senior administration officials via video teleconference Saturday about the hurricane, according to a White House readout of the meeting. Mr. Trump expressed that all departments and agencies involved should stay focused on saving lives, the White House said. 

Mr. Trump, who had been receiving updates from his chief of staff John Kelly Friday night and Saturday morning, directed his team to support the governors of Texas and Louisiana. Mr. Trump on Friday night signed a disaster declaration for the state of Texas at Gov. Greg Abbott's request. The declaration frees up federal resources to alleviate affected localities.

2:18 p.m.: Texas governor: No confirmation of fatalities; 338,000 without power
Texas Gov. Greg Abbott said he could not confirm any fatalities from now-Tropical Storm Harvey. He says 338,000 customers are without power and service might not be restored for several days.  

2:15 p.m.: Hotel taxes suspended for evacuees

Evacuees from areas affected by Harvey as well as first responders will be able to stay in hotels tax-free, Abbott says. He said he has waived the state's surcharge in a proclamation.

Abbott said about 1,500 evacuees are currently staying at Texas state park facilities. Nearly 1,500 more are staying in 21 Red Cross shelters and 42 more shelters are standing by to accept more evacuees. More than 200 buses have been deployed to transport residents, Abbott said.

2:13 p.m. 1,000 people involved in search and rescue operations

Abbott says 1,000 workers are focused on search and rescue operations, which he said "will be one of the foremost tasks that we take in the coming days."

2:10 p.m.: 1,800 service members to assist in recovery in Texas

Abbott says 1,300 Texas service members are already assisting in recovery and search and rescue efforts, with another 500 to be activated soon.

2:06 p.m.: Abbott says state concerned about 20 to 30 more inches of rain

"Turn around. Don't drown," the governor said. He says flooding is still a major concern.

"Now that the hurricane has come on shore our primary concern remains dramatic flooding," Abbott said. Abbott said about 20 inches of rain has already fallen in Corpus Christi and about 16 inches in Houston.

2:05 p.m.: Texas governor gives update on Harvey

Texas Gov. Greg Abbott provided an update on Harvey from Austin, Texas. 

1:50 p.m. Harvey downgraded to tropical storm

Harvey is now a tropical storm, the National Hurricane Center (NHC) says in its latest release.

Winds have slowed to 70 mph, down from a peak of 130 mph when Harvey made landfall late Friday. The storm is now located 45 miles north-northwest of Victoria, Texas, and moving at 2 mph.

But Texas isn't out of the woods yet. The NHC adds that an "extremely serious flooding event is unfolding" as the storm continues to drench the area in rain. Some areas have seen rainfall of up to 3 inches per hour at times. The threat of storm surge continues to threaten low-lying areas, as well.