Even though Hurricane Harvey was downgraded from Category 4 storm at landfall Friday night to Category 1 by early Saturday, the National Hurricane Center said water levels will still rise as torrential rain and blasting winds continue over the next days.

After battering the Gulf Coast of Texas, making landfall twice with wind speeds reaching 130 mph, the NHC said Harvey was now moving slowly over east Texas, at about 6 mph.

Southeastern Texas has already received 10 inches of rain (as of 5 a.m. EDT), and coastal cities could see 13 feet of storm surge and as much as 40 inches of rain by Wednesday, NHC said.

First responders are yet to assess the impact Harvey has caused over Texas since landfall, but forecasters said it will be devastating and leave areas "uninhabitable for weeks or months."

With prospects looking grim, if you want to help people affected by one of the most disastrous storms to strike the United States in more than a decade, there are a number of ways you can go about it.

The South Texas Blood, Texas is in dire need of blood donors at the moment, NBC affiliate News4SanAntonio reported.

According to STBTC, their blood reserve will last for a maximum of 24 hours. Due to an influx of patients in various hospitals in Corpus Christie, O negative and O positive blood are running at critically low levels. Interested donors can contact by calling 210-731-5590 or visiting SouthTexasBlood.org for more details.

Airbnb's Disaster Response Program is trying to help those who were forced to abandon their residence due to the hurricane by providing them temporary homes free of cost.

The program will accommodate disaster-struck people, including emergency relief workers and volunteers, in homes of hosts in San Antonio, Dallas and Austin until Sept. 1.

"Today, Airbnb activated our Disaster Response Program to assist residents in Texas evacuating coastal areas ahead of Hurricane Harvey,” Kellie Bentz, Airbnb head of Global Disaster Response and Relief, said, ABC affiliate KVUE reported. “We encourage hosts in safe, inland areas to aid in this effort by listing their available rooms or homes on the platform to help the growing number of evacuees. Our thoughts continue to be with everyone in the path of the storm, and we thank the dedicated government and emergency response personnel who are keeping our communities safe."

Photo: Getty Images/ MARK RALSTON

If you know anyone who might need to be temporarily relocated due to Hurricane Harvey, or you are willing to open up your home for those in need, you can click here.

If you want to be more hands-on in your assistance of those suffering due to the hurricane, you can register as a volunteer at the Red Cross or the Salvation Army .

These organizations are always looking for volunteers to help at shelters for the affected, and in distributing food, fresh water, clothes, bedding and other necessities.

If you want to help out by donating cash, all you need to do is visit redcross.org, call (800) RED CROSS or text the word "HARVEY" to 90999 to make a $10 donation.

American Red Cross has assigned hundreds of disaster-relief workers, provided tons of kitchen supplies and tens of thousands of ready-to-eat meals across the country whenever a region has been struck by a natural disaster.

With a hurricane and surge storm warning already in place Thursday, Red Cross of Eastern North Carolina deployed 23 volunteers and staff members to Texas and Louisiana before Harvey made landfall to help with rescue work. Most of the volunteers have been lending a hand to the charity organization ever since Hurricane Katrina tore through southeastern coast of the U.S. in 2004, leaving destruction behind.

"If it's anything like Katrina, and they're saying this is the worst since Katrina — and I have seen probably 40 of these things — I expect to see a lot of destruction," Zonia Ziada, American Red Cross volunteer told Eyewitness News. “They are opening mega-shelters for lots, lots of people to get out of the way of the storm.”